Money $100
Population 0 / 50
Day Day 1
Clock 00:00:00
Basin Breeding Basin
BG Equipped Background
Target Culling Targets
0 / 50
Hornwort Water Sprite
Click any medaka in the basin to inspect its genetics, or toggle Feed Mode to nourish your school and make them breed.

Time & Diet Controls

Food Standard Flake (+$1/bite)
Standard speed runs breeding checks every minute. Satiated fish will slowly digest their meals based on their digestion gene.

Inspected Medaka

Click a Medaka in the basin to inspect its color, fin structure, eye type, and digestive genetics.

Basin Census

Capacity50
Males0
Females0
Fry / Juveniles0
Carrying Eggs0
Spawning Mops0

Shop Broodstock Shop

Purchase starter pairs. True phenotypes often conceal recessive fin, eye, or iridophore alleles.

Diet Food & Nutrition Upgrades

Upgrade the quality of the pellets dropped in Feed Mode to increase earnings for every bite your fish consume.

Backgrounds Basin Backgrounds

Change the environmental conditions of your tank. Traditional Black Lacquer triggers background adaptation (*Haichi Hannou*), unlocking the chance to mutate Spots (Buchi) and Black Rim patterns!

Basins Basin Volume & Capacity

Speed Incubation & Time Speed Upgrades

Unlock advanced simulation speeds to accelerate line-breeding progress.

Plants Spawning Media & Moss

Genetics Genetic Loci Codex

0 / 44 Discovered

Breed new medaka pairings or purchase rare broodstock to unlock undiscovered alleles across all 6 genetic loci.

Notice Environmental Mutation Requirement: Spots and Black Rim will never mutate in light basins.
Notice The more plants the better: Reaching at least level 15 in all plants lets your fish unlock the chance to mutate into a special form!

Achievements Breeder Awards

Unlock milestones for feeding your school, isolating rare alleles, and breeding legendary show strains.

Settings Options

50%
50%
Light Mode

Export your line-breeding save file to your local computer so browser cache wipes never erase your progress.