AQUA·GENE

Every fish in this game is drawn from its own genome. There is no fish art with a fish's name on it, and no fixed list of species. Body, fins, pattern, eye, colour, size and temperament are genes with two alleles each, inherited 50/50 from two parents — and what swims in your tank is whatever those alleles resolve to.

Buy fish. Keep them fed and their water clean. Pair two, incubate the egg, and find out what you made.

The hook: shimmer is recessive

Shimmer only shows when a fish has two copies of it. One copy makes a carrier — a fish that looks completely plain, is worth almost nothing, and is the only route you will ever have to an iridescent one.

So the fish worth breeding are rarely the fish worth looking at. That is the whole game. The Genetics screen does the Punnett maths for you and tells you the truth: real odds, computed from the same allele arrays the breeding roll actually uses.

The shape is heritable, not a menu pick

Four genes choose an archetype — torpedo, round, flat or fancy; four fin sets; four patterns. The rest are continuous, and they bend it: body depth, taper, tail fork, eye size, fin length. A "round, fan-finned" fish isn't one fish, it's a continuum of them.

And because fin length is polygenic — three genes averaged — a lineage can be bred toward a fin no founder was born with and no shop will ever sell. Keep the best fry, breed it again, fourteen generations later you have a longfin that did not exist when you started. Selection does work the RNG can't.

What's in it

- Multiple tanks, quarantine, and a sickbay — disease is real and neglect kills

- A hatchery with incubation you can pay to hurry

- A codex that logs every species you meet, bought or bred or merely offered

- A gene lab that fabricates true-breeding founders, for gems

- Quests, achievements, beauty tournaments, tank compatibility, decor, shrimp

- A save that round-trips your genomes exactly

Under the hood

Native Windows app — C++20 and SDL3, no engine, no runtime to install, 3 MB download. The genetics are golden-tested against the original prototype allele-for-allele. The art is palette-locked and gate-checked: a sprite that reads as the wrong body shape fails the build.

Made in the spirit of Maxis' El-Fish (1993), which had the right idea thirty years early.

Windows 10/11, 64-bit. Unzip anywhere and run AquaGene.exe — keep it next to the assets folder. Saves live in %LOCALAPPDATA%\AquaGene. The build isn't code-signed, so SmartScreen may want a "More info → Run anyway".