Upstream (Trout egg Regression TF)

Story by Gabriel Moon on SoFurry

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#17 of Commissions

A woman willingly undergoes a nantie-induced regression into a trout egg to experience the life cycle of a fish first hand


Cassie took a deep breath before feeling the familiar tingle of the nanites at work in her system. She was alone in the test chamber, with no cameras or speakers, but that suited her just fine. She didn't need to see her colleagues' reactions to the process. The nanites would record all relevant data, anyway.

It gave her a brief time for introspection before the transition began. Part of her mind wanted to take a moment and rethink the task, but it was far too late to back out. It was a frightening prospect to give up months of her life for the assignment. And for most, it was unthinkable to undergo such a drastic change. And to willingly sign up for it...but no. Cassie had made up her mind weeks ago.

Her first-hand accounts, along with the data acquired through the nanite program, would be invaluable. She'd already resolved herself to undergo the procedure, having already made the necessary arrangements in her personal life to be away for the several-month experiment. And besides, it was a once in a lifetime experience. How could she not be at least a little excited?

Since the advent of nanite technology, there had been numerous scientific advances in the fields of biology and medicine. Most genetic diseases could be cured, shortages of supplies and food were a thing of the past, and humanity as a whole was free to spend their time with personal pursuits. As a species, many decided to use their freedom to explore a variety of scientific and artistic endeavors.

One such scientific branch involved using the technology to change one's body into another completely non-human animal. The idea was to explore the world through the eyes of an animal, a way to study other lifeforms that were previously not dreamed of. And for Cassie, it had been a life-long dream to join a team conducting those very experiments.

For this experiment, the nanites would regress her body into that of a trout egg. She would be transported to a nearby stream as soon as the change was completed. There, she would live the entire life cycle of a trout, experiencing it first hand with all her memories intact. Though she would be in control of her body, the instincts of the fish Cassie would become would guide her actions. The experiment was set to end once she reached adulthood and returned to the initial site to spawn.

The process, though not without risk, was as safe as possible, given the drastic nature of the experiment. The nanites stored all aspects of her consciousness; so long as one survived, the nanites had the capacity to self replicate indefinitely. Even if she was eaten or killed, Cassie could regenerate to continue the experiment.

The idea of experiencing life as another creature, even as banal as a fish, was powerfully appealing. If she was to do well at this assignment, there was every chance that she would be selected to participate in future transformation experiments. It was not something she wanted to pass up.

A dizzying sensation started to overtake her, and Cassie was broken from her reverie. She was disoriented for a moment before the realization hit her that the nanites were taking effect. It seemed as though the room was expanding around her from all dimensions. She had a long way to go before she reached the required size. Thankfully, the process was entirely painless. It would be impossible to fathom undergoing the transformation otherwise!

As she shrank, Cassie was aware she was losing muscle mass throughout her entire body. Her breasts started to tingle as they lost their fat and began to deflate into her chest. Yet, even after rubbing them, their presence did not seem to fade entirely. They were smaller, reminding her of their appearance just entering puberty. They still maintained the familiar points of nipples, though they were sat upon an entirely flat chest.

The sensations swelling from her groin removed any sensitivity she processed down there. It was as though the hormones in her body were being rewritten, regressing to a state before she hit maturity in her teenage years. She was not only changing species, but returning to a prior state of her own human development first!

Her body was steadily shrinking, losing inches as the minutes passed. She was about the height of her 10-year-old self now, and her anatomy was beginning to reflect that. Her skin was smooth, her body hairless save for her head. The freckles she had as a child returned to her face, and her hair became immaculate, lacking any of the wear of her adult self. It was a nostalgic sensation, to return to a form that she barely recalled possessing at the time.

The changes carried on more rapidly now, forcing Cassie to cope with the extreme disorientation from her loss in stature. She was less than 4 years old now and continuing to shrink. Her previously lithe form was growing chubbier as Cassie returned to the dimensions she possessed as a toddler. She tried to speak, but her voice came out high pitched in a way that left her extremely discomforted.

Two years old now, Cassie found it troublesome to stand as the muscles in her body started to lose their development. Her flesh became pudgy, adding its baby fat as the hair on her head retreated back into her scalp. Her head was much larger concerning her body as she toppled over, unable to stand or walk without the proper support.

As she repressed past a one-year-old, Cassie was aware of an unusual discoloration spreading over her flesh, a stark contrast to her human skin. It seemed her species was finally beginning to alter. Her spine started to extend, though the bones within were dissolving as the growth protruded beyond half the length of her current form.

At 6 months now, her skin was entirely orange as her head started to bulge out, her lips and nose forming some sort of snout. 1 month old, her legs and arms stopped moving, the physiology of a fish taking over the infant human shape she had acquired.

The expansive room started to darken as her eyes became vestigial. She had prepared for this, but it was nearly impossible to fully comprehend what it would be like to be blind. She was truly helpless, barely able to move as her legs and arms reduced to stumps, and then nothing. The receding bone and muscle all throughout left her no longer able to move. She could no longer even wag her tail, open her mouth, or twitch her body.

Her senses were reduced to mere tactile experiences, but even those were dwindling from lack of nerves in her underdeveloped body. Cassie would not have known her torso was extending relative to her body, or that her spine was now a simple notochord, had she not researched the assignment in great detail before. She lacked even the basic sense of touch to be aware she was lying along the floor.

Yet, there was one sensation that still entered her awareness. It was as though her body was oozing a gelatinous substance, one that covered her entire being. It felt alarming to her psyche as it proceeded to envelop her in what her human mind knew to be an egg capsule. She would be completely encased, unable to interact with the world. It was akin to a nightmare from which she could not wake.Yet those words failed to describe the horror. Even in a nightmare, she could see, could hear, or smell. In this egg, she would experience almost nothing.

As the gelatinous fluid continued to ooze from the remnants of her flesh, something else began to emerge as a weight on her lower half. It was attached directly to her insides as it swelled larger than her entire body. As it completed its progress, it began pumping what Cassie knew to be life-giving nutrients into her helpless form. It fed its resources directly into her, giving her all her developing body required. She would exist entirely on this yolk sack for the duration of her time as egg, and even into her juvenile trout life.

The egg continued to envelop her body, forcing it to contract in on itself. She could barely feel that her tail was nearly in front of her where her face was. It was far thinner than her head, which itself was a relatively bulbous structure with the remnants of her eyes on either side. Yet, in their vestigial state, they could not perceive the world around her in a meaningful way. Only the egg around her and her swelling egg yolk was known to her.

With that, the changes were complete. Cassie was entirely transformed into a fertilized trout egg, nothing but an embryo persisting only on the yolk sac that covered her belly. She had no concept of the world beyond her gooey egg. Cassie knew that she would be taken to the water, to be placed in a stream with millions of other eggs of her species. But she had no way to tell when that occurred. Even being placed in the water would not trigger her senses. Her only knowledge of her successful placement was that her egg had not become desiccated. Even if the nanites repaired it right away, she was certain the dryness would be overwhelmingly alarming.

Cassie didn't know how long she stayed there, her egg sitting among millions of others that she was unable to see or hear. It was extremely unnerving to be so cut off from the world. The passing of days, changes to her watery environment, and the presence of predators that might find her egg a tasty treat was all beyond her reach. She feared she might go mad from the sheer terror of the nothingness. It was truly purgatory, with no outside stimuli to satisfy the parts of her memory that craved such contact.

Cassie had first tried to occupy her thoughts with things like movies, books, tv shows. Any of the hobbies she loved, the stories, and fiction that allowed her an escape from her nightmarish reality. Cassie even developed games to try to maintain some semblance of sanity in her personal hell. Yet, no matter how she tried, it was impossible to fill the vast nothing that had become her world. The silence was near maddening.

The eggshell she was in was her whole world, its own self-contained ecosystem. As time passed, that realization came to the forefront of her daily thoughts. Cassie found it increasingly harder to worry about life beyond those walls. Soon, her mind started to shut down, her thoughts becoming foggy as she began to realize that there was nothing beyond this egg that mattered. The yoke sac provided all the nutrients she could ever need, eliminated her waste, and kept all her bodily functions intact. What more could anyone possibly need?

With that, Cassie found herself experiencing a kind of inner peace that far surpassed the human fear of loss. It was akin to being in the womb, only this time she was semi-cognizant of the experience. It brought a level of comfort that no human had likely ever experienced.

All the while, she continued to grow, her body developing as it fed on the yolk. Her eyes slowly took in the world around her, though they could no longer blink. Color was lost to her, with only the lightening shade within the egg to denote their development. She was thankful for that, knowing her current stage of development left her skin translucent. She didn't need the mental image of seeing her internals organs, her spine, and brain visible before her eyes!

The features on her head were slowly growing more pronounced, creating a distinct line for gills, a separation from her trunk, and a longer tail. It was still impossible to smell or hear, but her senses seemed to slowly be preparing themselves for life beyond the egg. Cassie felt herself growing excited at the prospect. She would kill to be able to hear or see at even a fraction of her former ability once more!

She had no concept of how long she'd been an egg. As time passed, it became harder to recall what life beyond its boundaries was like. It seemed like an out of body experience, a memory from another life. Yet as the days passed and her body developed through nutrients fed into her system, the memories returned. She recalled the autonomy she'd enjoyed, and part of her longed for it again. As peaceful as life had been, the natural progression was to develop and grow and experience all the world had to offer.

Her body grew a bit more each day as her form gained strength. She could almost feel her muscles tensing as they prepared for her eventual fate beyond this capsule. Her body even started to move now and then, her tail and torso thrashing back and forth as her body slowly developed. The larger she grew, the greater her desire became to explore beyond the confines of the egg.

She was surprised when it actually happened. One day, her wriggling body simply tore a hole in the haven of her shell. With a fluid motion, she forced herself out of the gelatin and swam in the water. With that, she knew she had officially progressed to the alevin stage.

The temperature of the water was perfect, making her feel comforted and relaxed in her new home. Her eyes weren't too developed, but she could make out vague shapes in the water around her, ones that her human mind seemed to determine were rocks. Though given her size, they were likely only pieces of gravel.

She could still feel the familiar weight of the yolk sack on her belly, the one that had given her life in the egg. Part of her human recollection reminded her that it would continue to be a source of food for some time. It would nourish the level of development she would need to strengthen her eventual escape from the gravel that comprised her hatchery.

There was little for her to explore in the alevin stage. She was in a daze those first few days, swimming lightly with her limited senses. She knew both instinctively and from memory that it was a poor idea to move beyond the gravel pit she had found herself in. And she had no need to leave her, her yolk sac able to provide all her needs.

Still, it was a great comfort to see her environment slowly coming into focus. Her eyesight had improved significantly, and she was thankful for the piscine lenses that allowed her vision in a watery world. Colors were muted, muddy, and it took some days to make sense of things in human terms. Her head could almost move of its own accord now as she explored the rocky floor of her home. It aided in alleviating the boredom she was condemned to in this state of being.

Massive spires of green towered over her, looking more like trees. It was surprisingly difficult to distinguish them as grasses and reeds from her underwater perspective. To her trout mind, they invoked a sense of safety.

Similarly, the floor of the river was full of boulders, with enough space for her to hide and rest if she desired it. Her world was shared with a myriad of other invertebrates, things smaller than her and relatively harmless. And naturally, her fellows were present as eggs and alevins, hidden in the reeds and boulders as she.

Her other senses were surprisingly acute, though she expected they would continue to develop as she aged. She could smell, at least to a degree. The molecules in the water were alien to her human mind, and even her trout instincts could not properly distinguish them yet. One familiar odor, one she recognized as her fellows, was ever-present. With some effort, she could distinguish individuals easier through scent than with her sight. She could hear as well, though mostly the sounds of crawling creatures moving the boulders that attracted her ears. Anything beyond this safe haven was lost to her senses as an alevin.

As the days steadily carried on, she was aware her yolk sac was dwindling in size as her entire body sucked out its nutrients. It would only last her for so long, a period of days or weeks as opposed to the months that it would take for her brethren to develop. Each day she felt her body grow stronger, her tail able to better propel herself forward.

Cassie could tell her body was continuing to grow, though it was difficult to see the changes in her form. The color of her skin was starting to change, darkening from its original orange towards a brown shade. The flesh was no longer translucent now, which Cassie was grateful for. Her innards were not something she needed to see for the rest of her piscine life.

The actions of her fellow alevin took up most of her daily attention. Like her, they seemed content within the boundaries of their hatchery, learning their world as they slowly developed. Occasionally, she saw them leaving the confines of their shallow depression, but did not yet have the urge to join them. It was only a few in number at first, but as time went on, more and more of them left their safety for what beckoned beyond.

It became obvious to Cassie that her body was preparing for that same journey. Eventually, near the end of her yolk-sac reservoir, she was driven to leave. It was mostly from a place of hunger, but also from the very human boredom of remaining here too long. The piscine parts of her psyche craved something that this habitat could not provide, while the human was eager to explore the world beyond this tiny depression.

Cassie braced herself before taking that critical first swim towards higher waters. By now, she had become somewhat accustomed to using her new tail to propel herself. Yet this was a more urgent need, and her new appendage moved more frantically than at any point in her life.

Deep down, she was able to discern the dangers of such a swim. It was her first time leaving the safety of the nesting grounds, and the first real experience she would have with the threat of predation. She knew the nanites would keep her safe, yet she had no desire to experience being eaten and reconstituted nonetheless!

Moving beyond the confines of her birthplace was insufficient for her instincts. Her mind seemed content on reaching the heavens, a brilliant sphere that seemed a continent away to her tiny body. Cassie started to realize that she was being compelled towards the surface, yet had no idea why. She didn't need to breach into air if she could breathe through her gills, right?

Yet the reason for her ascension became clear. It was a Herculean task to rise to the surface as she currently lacked buoyancy. A trout lacked the energy required to prevent sinking to the bottom of the river on their own. She was required to take this initial excursion to the surface, to fill her body was the air necessary to fill her swim bladder. It was referred to as a 'bottom-up' event, one that marked her transition into her next life stage.

As she ascended, Cassie could better make out the barrier above her. The water became more difficult to traverse the further she rose to the surface, and she could make out several of her fellows being swept further from her horizontally. She assumed she was in a shallow part of the river; anything further out would send her downstream, far away from the safety of her gravel. But even so, it was difficult to reach her destination with her tiny body.

Her visual capabilities as a trout became easier to understand the more she grew accustomed to moving in three dimensions. It was easy to see the barrier above her, but harder to see the shapes of other alevin ascending with her. But potential threats weren't from others of her kind, and she cared little for their own journeys. Her goal was only that brilliant wavering form above her.

At last, her mouth hit the surface, and for a moment, she panicked. She could not see anything above her; that world was beyond the perception of her piscine eyes. She did not raise any further, worried for her mortality should her gills breach the surface, but her gaping mouth was sufficient to draw in the oxygen she required.

It was a terribly frightening prospect to remain so exposed, but she was compelled due to the necessity of oxygen intake even over her fears for self-preservation. It was evident to the vibrations in the water that something relatively massive was nearby, removing her hatchery mates as it ate its fill. Evidently, predators made their living waiting for alevins such as she to breach the surface, looking to pick them off. Again, Cassie found herself afraid for her life. The idea of being eaten and digested was not a pleasant one. Though she would not perish, due to the nanites, it was still not something she wished to experience first hand!

Soon, her swim bladder had its fill, and she was able to descend to safety, leaving the now alien world behind. Life after that started to change rapidly. She was hungry, terribly so, and compelled to eat zooplankton, tiny organisms that evaded the human eye. There were literally billions of them in her small corner of the river, enough to satisfy even her appetite. Her body was still too small to go beyond the calm river water near the shore, and not large enough to evade danger. Rocks, reeds, and trailing plants were her cover as she fed.

Her senses had been steadily advancing as time passed, and the world was slowly starting to translate to her prior human knowledge. Though her vision was muddied, she could still see the world above and below her with clarity. Threats to her life came from those angles. Her side to side vision was not nearly as acute, due to its lack of evolutionary importance.

She was better able to distinguish scents as well, not just the ones of her hatchling-mates. Soon, the unique pheromones of predators were committed to memory, larger fish, insects, and frogs of particular threats. She soon learned to avoid them, her human knowledge allowing her to seek shelter at the slightest hints of their scent molecules in the water.

One sense that took some effort to adapt to was her hearing. It was different than the human equivalent, more sensitive to vibrations in the water rather than sounds in a manner that humans were accustomed to. But she found, to her delight, that they were far more useful. She existed in three dimensions, able to move up and down as well as back and forth. The direction from which she detected vibrations became far more accessible to her.

Yet far superior to her hearing was a new sense, one that her human self could not make heads or tails of. A tingle along the sides of her body allowed her to detect the location of other fish relative to herself. Her human mind recalled the research she had done on lateral lines, electrical signals that fish used as another form of locational sense. But to actually experience it was something different entirely! In tandem with her smell and hearing, she had a much wider view of her surroundings than a human in a wetsuit could ever hope to achieve!

Though she had not been predated, many of her fellows were not so lucky. Often, she felt the vibrations of something dangerous approaching, and her human awareness with piscine instincts were sufficient to avoid potential threats. But dozens, if not hundreds, of the fry nearby were denied such escape. Yet Cassie found she cared very little about their fates. Trout juveniles had a very high rate of mortality, and there was every chance that every alevin she had hatched with would perish. Less than 5 percent of her species would reach adulthood, claim territory in the river, and eventually spawn.

The power in her body had been steadily increasing as the days went on. Her tail started to sport a fin-like appendage, while several other sets seemed to form from the light protuberances her juvenile body was born with. She had eight fins in all, four swelled from the tissue that would have made her mammalian limbs, one dorsal and one caudal, with two additional fins in between. She was thankful for their presence as her body continued to develop, and her needs to traverse greater territory increased. The additional fins allowed her to steer, to better control her piscine body as she explored her new environment.

She had grown larger by this point, faster than the other fry she had hatched with. She assumed she was beyond the fingerling stage now, closer to what was known as parr. With her increase in mass came several changes to her lifestyle. For one, her hunger had grown, and the zooplankton no longer sufficed to feed her. Her instincts demand she feed on insects, larva, and other invertebrates, something the human part of her found revolting. Cassie was aware it was a part of her new physiology, but one that she did not have to like. She still kept low to the gravel as she hunted for her prey, but now, her larger size was sufficient to venture out into deeper waters.

Her body color had metamorphosed, but her awareness of it was a product of her recollection. She could see the shades of her body as it moved, but its distinctive patterns were lost to her field of focus. Still, she knew her scales were likely peppered by fingerprint patterns on the side, ones that would eventually fade into the black spots of the adult trout. It was almost like a rite of passage, one that gave her a strange sense of pride.

Another startling change was how defensive she felt about her space. Before, the presence of other parr did not bother her so much. But now, whenever their pheromones touched her nose, or her lateral line detected their proximity, she felt anger. No, it was not human anger, not exactly. She was compelled to assault them, swimming rapidly and pushing them away, or biting with her gummy jaw until they fled. Her human mind knew she was potentially attracting unwanted attention from predators, but it was worth the risk, to keep others from her space. She needed a territory to feed on, or else she would not have sufficient food to grow!

This stage of her life was by far more dynamic and interesting than her juvenile life had been. She spent the time exploring, marking the bounties of her land with active aggression. It gave her a sense of purpose, to explore this space, to eat, and to push away any intruders. Her territory did not have defined borders, so she had to patrol its perceived boundaries constantly. And exploring the ranges she could feasibly defend, learning its topography, and translating her piscine sensory inputs to human experience was a task that satisfied even her human intellect!

Yet the more she grew, the duller her piscine life became. She finally had a suitable territory; she dared not leave its confines lest she lost it to another trout. Therefore, she could not explore the rest of the river, or all it had to offer like the human part of her mind wished to. It became boring in the ensuing months, to know every inch of this space and unable to traverse further.

Yet the piscine part of her mind saw things differently, and that contrast allowed her to maintain a semblance of sanity. Her trout self relished the idea of having a boundary, defending it from rivals while remaining relatively hidden from potential predators. The larger she grew, the easier it became to protect her territory and map out places of relative safety. She had the added advantage of maturing far faster than her fellows, her larger size able to compete with any of the remaining parr and even some of the other adults, in tandem with human intellect.

Cassie was vaguely aware that summer was steadily passing, though the season had different implications for her underwater life. She was certain that she was coming into her adult colors as the water warmed and became more shallow. Her scales would be darker on top, speckled with black dots as befit her species. It made her hidden to predators from above, as best she could be. Her larger size saw no underwater threats, her species the apex being in this watery habitat.

The shallow depressions in the summer river served her piscine needs well, and she was compelled to seek them out. Often, she would position her head upstream, the cavity fitting her body and allowing little additional energy to maintain her position. From there, food would flow into her mouth, invertebrates that tasted little to her tongue but helped to fill her up. She was getting used to the disgusting crawling feeling in her mouth before they were forced into her gullet. Her previous disgust was slowly waning, which was thankful. She spent so much of her time eating, and her existence would have been maddening otherwise.

Life continued much in the same fashion for many months. Though there were times she needed to move, to push out intruders from the best depressions, the quality of her existence was monotonous at best. She longed for sleep, for the rapid passage of time that allowed her human cognizance a brief reprieve. It was a substandard existence to live in longing for tomorrow, for the next stage of her development.

Yet, in contrast to the monotony, she found something oddly peaceful, existing as a fish, all of her cares and troubles a distant memory. Aside from an invading trout, or the shadow of a hawk looking for piscine prey, there was little she needed to worry about. Food literally swept into her mouth without her needing to hunt. It became somewhat of a luxury unknown to human life, to allow herself to go, to live in the knowledge that existing without struggle was sufficient. It was like a vacation of sorts, beyond anything a human could ever enjoy. Cassie allowed her human thoughts to drift for days at a time, surfacing only when needed, finding some peace with piscine life that she never expected.

At last, after months of existing as an adult, the colder November water signaled a change in her physiology, one she had been anticipating with some excitement. The peace of her watery home was no longer required for this next stage of life. It inspired her to move into deeper waters, traveling upstream to an area she had not explored. Yet part of her found the journey familiar, as though she was returning to the place of her birth.

The need to travel was spurred by a desire in her loins. She had not been granted pleasures of the flesh in her time as a trout. In truth, she longed-for the contractions of orgasm. Though normally, trout would require an extra year to reach sexual maturity, the nanite program allowed her the luxury of being able to lay eggs in her first year. Her time as a trout was nearly over.

As she swam, the feelings of other piscine bodies touching her gave her pause. Though this time, she felt none of the previous aggression at their presence. She knew it was a risk to spawn, that so many of her kind in one place would provide a smorgasbord of morsels for any predators. Indeed, she felt the vibrations of a large beast in the river, swiping at her kind as it ate its fill. She assumed it was a bear, a deadly predator for her kind. To her dismay, she found she had to avoid more than one as she continued her trek upstream.

Yet soon, she found it, the place her instincts beckoned her towards. It was a relatively shallow area, rich with gravel deposits, similar to the one that she had risen from several months ago. It took her a few moments of scouring the area, but at last, she found the ideal spot. Oxygen-rich water flowed over where she would make her redd. She lowered herself towards the river floor, rubbing at it with her anal fin. The impression needed to be deep enough to allow her eggs the best chance at survival.

Finally, her twitching, writhing body was done, at least to her trout psyche. It was now a sufficient depression that she could lay her eggs into without risk of them being swept away. Her loins had been quivering all this time, beckoning her to place her vent over the hole. Both the nanite-created piscine instincts and the human Cassie were elated with the idea of laying. She could feel them swelling in her body, her ovaries preparing to churn them out to complete her final task as a trout.

The quivering in her vent rose to a crescendo as the first of her clutch began to descent. Cassie could not have anticipated how good it felt to a fish to lay her eggs! She would have moaned if she could, but her mouth could only open and close in ecstasy. Her insides writhed with the sensations of eggs passing the inner walls, and with delight, the first clutch of slimy, gelatinous eggs fell from her vent and settled into the gravel below.

Her entire body writhed in an orgasmic release as the next clutch of eggs started pushing from her ovaries, prepared to exit her vent, and fell to the gravel below. This clutch seemed larger than the last, and although it did not cause her pain, it did stretch her insides impossibly wide. Yet it only served to accentuate her pleasure to lay so many eggs at a time. Another clutch fell from her vent, the stirrings of the next few hot on their heels.

Cassie had no idea how long she lay there, her body wracked with the pleasures of orgasm as she laid clutch after clutch. She knew one trout could lay hundreds of eggs, and they had been developing silently in her sex for the past several months. It would take literal hours for the task to complete, and each wave felt better than the last over her fishy body. It was far beyond any orgasmic sensation she knew from her humanity, almost worth the long wait for this one annual spawning session!

Finally, after an eternity of orgasmic bliss, she felt the contractions diminishing. Spent, she rose from her place, smelling what her senses told her was a male, one that had won the right from several other males to fertilize her clutch. She could scent the thick, spicy scent of milt as the male lay over her redd, spilling load after load of milky white fluid to be washed over her orange eggs. It seemed evident that his body, too, was wracked with the same ecstasy as she had been, though it was impossible to be certain. One thing she did know was that the length of time he knew it paled in comparison to her own.

Afterward, Cassie was compelled to descend to the redd once more, needing to cover her clutch as a final act of parenthood. Using her anal fin and twisting her body, she pushed the gravel back over her eggs, doing her best to cover them. Her mind was eager to erase the orange from the sandy bottom to allow her clutch the best chance of survival before leaving the potential next generation to their fates.

Afterward, Cassie lay there, hovering in the post-orgasmic bliss of having completed her life's purpose. Though she would not die, perhaps having a few more spawning sessions left in her, she felt a sense of completion that made her smile inwardly. It was so fulfilling, she hardly noticed the tingling of nanites as their trigger activated them, and she began her reversion to her human self.

Her body grew massive, making it harder to float there as her dorsal fin breached the surface of the water. The wind against her scales made her shiver, but soon they melted into her form to make room for equally chilly human skin. Her tail stopped thrashing in the water as it receded into her asscheeks while her legs and arms scrapped across the gravel, returning to their human shapes. She coughed for a few moments as her gills receded, her body no longer designed to survive underwater. Thankfully, her body had developed sufficient muscle to lift her head above water, and she breathed deeply in the air for the first time in months.

Cassie rose to her knees, slowly able to take in the world as her eyes shrank relative to her body, and her nose formed on the end of her receding muzzle. She gagged a little, the piscine stench above water offensive to her human senses. But soon, the rest of her scales receded, and her skin-covered body no longer exuded that distinctive stench. She drank in the surface world through human eyes, disoriented to see what literally felt like the other side in perfect clarity.

Familiar sights entered her eyes, and Cassie looked up into the faces of her coworkers as they helped her up to her feet. Handing her a coffee and wrapping her in a towel, they allowed her a few moments to regain her balance. It took some time to readjust to a bipedal stance, even though her muscles and bones were none the worse for wear from the transformation. In some ways, she found herself missing the three-dimensional travel she enjoyed as fish. But, it was time to return to human life. For now, at least.

As she was led towards the car, Cassie resisted the urge to rub the flesh around her crotch. The nanites provided her a wetsuit of sorts, to protect her modesty. But something grainy was rubbing against the surface between it and the flesh of her groin. She did her best to make conversation with her coworkers, distracting them as she drew her fingers discreetly downwards. It was nearly impossible to stifle a moan of pleasure as her fingers cleared away a small pile of trout eggs from her groin, making room for the rest of them to fall from her vagina.

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Cassie felt the cool splash of water on her gills as her shrinking body hit the waves. Her scales were not hindered by the cold, however, as she made her way to the bottom of the artificial stream. Her stretching tail propelled her forward, as she swam happily, eager to return to even a brief time of piscine life!

Her colleague, Tyler, had been surprised to hear she wanted to change back, especially so soon after her assignment. But, her debrief showed her to be perfectly sound in body and mind. Once the reports had been written, she was entitled to vacation time. And she had access to a variety of nanite programs she could use for recreational purposes. So, after a bit of persuasion, she was allowed to live in the office freshwater tank as a sort of pet.

There was another reason she wanted to return to the state where she'd been those last few days of her life as a trout. She had to be discrete about the actions, lest she alerted her colleagues to her rather embarrassing hobby. It had been something she'd designed the nanite program to do, something easily overlooked from any developer.

She had to make sure to resist the urges until night, while she was left alone in the tank. Even her limited piscine sense could tell when the lights were off, and when she knew she would not be seen. The urges in her loins would not be kept at bay much longer.

Completely on instinct, she made her way to the bottom of the tank, her fins making a sizable indent while her cloaca screamed at her with the promise of pleasure. One the impression had been dug to her mind's content, she relaxed, allowing that perfect fulfillment to flow over her body as her vent started to twitch and throb and ooze out the first of many egg clutches she would lay that night.

It seemed that her nocturnal activities did not go unnoticed for long. One light, she felt the vibrations from a slap above as a form more massive than her own hit the surface of the water. But soon, it began to shrink towards dimensions that she found more familiar. Though it was difficult to make out, her eyes did discern a descending shape that was a mix of both man and fish. Soon, it took on the dimensions she understood as a trout like she was. And from the pheromones in the water, she could tell it was a mature male.

Soon, a familiar spicy scent hit her nose as the male swam over to her clutch. Uncontested for the right to mate, he spilled his milt over the eggs, writhing in pleasure as he did so. His body shook and thrashed in the water, thick clouds of trout cum landing over the eggs. Though they would not hatch and mature, due to the nanite program she had adjusted, it was still evidently powerfully arousing for the male to fertilize them.

The sight and smell of him lit up Cassie's loins once more. She had no idea who had joined her on vacation as a trout. Most likely, it was Tyler, having discovered her desire to procreate over and over each night. Perhaps he was curious about experiencing his own orgasmic release as a trout.

Whatever the reason, Cassie cared little. What mattered most was how his sight and scent turned her on. The knowledge that a male was here to fertilize her clutch was a more potent aphrodisiac than she could have ever anticipated. Cassie felt the urgent need in her loins to lay more gooey eggs as her body started contracting with the upcoming orgasm. She would certainly be laying many more times tonight!