In development · iOS & Android
A quiet koi pond in your pocket.
Watch the water, feed your fish and breed koi no one else has. Nothing is lost while you’re away.
These koi were made for this visit only. In the app, your koi stay with you.
Heredity
One of a kind, and still family.
Every Koiyo koi carries a genome — pattern, colour, fins, even the way it swims. Fry inherit from both parents, so they look like family, yet each one is its own.
This preview is simplified and runs entirely in your browser. In the app, every pairing is recorded by our server, so each koi and its pedigree stay unique. A pairing brings one fry, and the parents rest afterwards.
Together
Two phones, one pond.
Meet a friend and bring your ponds together. Your koi swim side by side — and if you both agree, they can have fry, with both ponds in the pedigree.
We’re also experimenting with phones lying side by side on a table, so koi can swim from one screen to the next. Breeding always needs both owners to say yes.
Care without pressure
Unhurried, by design.
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Your koi never die.
Miss a day or a season. The pond simply waits for you.
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No streaks. No countdowns.
Nothing you’ve grown fades, and nothing nags. Come back whenever you like.
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Quiet by default.
Notifications stay off until you choose what, if anything, you want to hear about.
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Breeding is your choice.
Koi never multiply on their own. Every pairing is deliberate.
Night pond
Some koi keep a secret until dark.
Switch the pond to night whenever you like. Rare koi carry a hidden trait: by day their patterns shimmer like pearl, after dark they softly glow.
Night is a switch, not a schedule. You never need to visit at a certain hour.
By day
At night