GROWING YOUR TANK

Drag into the tank, or tap to drop in

Build your own living fish tank.

Drop in fish, plants and stone and watch your tank come alive. Then meet every fish and learn what makes it amazing.

From empty glass to a living tank.

Build it, bring it to life, and learn as you go.

Build your scape

Drop in fish, plants, wood and stone. The water, light and current respond in real time, so your tank looks and moves like the real thing.

Watch it come alive

Your fish swim, your plants sway, and the light shifts. Feed the fish, change the lighting, and rearrange your tank however you like.

Meet every fish

Tap any fish to open its page and discover where it lives, what it eats and the wild facts that make it special.

Fish of the week.

A hub for people who love fish. Each week we feature a stunning species, some you can keep and some you can only marvel at.

This week

Reef jewel · Western Pacific

Mandarinfish

Synchiropus splendidus

Reef aquarium · expert only

Origin: Western Pacific reefs
Adult size: 2.5 in · 6 cm
Habitat: Coral lagoons, marine
Temperament: Peaceful, shy
Diet: Live copepods, micro-predator
Care level: Expert
Lifespan: 2 to 4 yrs
Reef safe: Yes

One of the reef's living jewels: a thumb-sized dragonet that threads through coral rubble at dusk, painted in maze-like swirls of electric blue, tangerine and green.

It spends the day picking microscopic copepods off live rock one by one. That slow, live-only appetite is what makes it a fish for patient, well-established reef tanks rather than beginners.

Its blue is a true cellular pigment, not reflected light, making it one of very few animals on Earth that build blue this way.
It has no scales; instead it wears a thick, foul-tasting mucus that fends off predators and parasites.
At dusk, pairs rise together in a slow courtship dance before releasing their eggs into the current.

Read the full profile →

The rankings.

One vote a day. Back your favourite fish, push it up the board, and keep your streak alive. Fans decide who wears the crown as Fish of the Week.

This week · top 10Full leaderboard →

Explore the fish.

Filter by where they live or how easy they are to keep, then tap any fish to learn all about it.

Who can live together?

Not every fish gets along. Pick two and find out if they'd share a happy tank.

Fish one

Fish two

Test your fish knowledge.

Eight questions. How many can you get right?

Dive into a habitat.

From Amazon rivers to the pitch-black deep sea, every fish comes from somewhere. Explore by habitat.

Get to know your fish and plants.

Friendly guides for the fish and plants in the tank, each with a fact sheet, care notes and an FAQ.

Betta care guideFish

Angelfish care guideFish

Cherry shrimp careInvertebrates

Java fern care guidePlants

Amazon sword guidePlants

Substrate guideSetup

Browse all care guides →

Questions, answered.

New to fish, or just curious? Start here.

What is Yunofish?

Yunofish is a free online playground where you build your own living fish tank in the browser, then tap any fish to learn how it really lives. It is a fun, hands-on way to explore the underwater world.

Do I need to know anything about fish to start?

Not at all. Drop in whatever fish, plants and stones you like and watch your tank come alive. As you build, you can open each fish's page to discover where it lives, what it eats and the wild facts that make it special.

Can I really keep all these fish together in real life?

Not always. Use the "Who can live together?" checker to find out. Saltwater and freshwater fish cannot share a tank, and a big hungry fish will often eat a tiny one, so part of the fun is learning who makes a good tankmate.

Are the fish facts real?

Yes. Every fish, shark and deep-sea creature has its own page written from real, well-established science, in a friendly way that is easy to understand.

Why can't I keep a shark or an anglerfish?

Some animals here are wild ones you meet just to learn about, not pets. They are marked "Wild" and are far too big, too specialised, or live somewhere (like the deep sea) that no home tank could ever recreate.

Can I save or share my tank?

You can save tanks in your browser right now. Saving to an account and sharing your tank with friends are on the way.

Is Yunofish good for kids and classrooms?

Absolutely. It is built to be safe, friendly and genuinely educational, perfect for curious kids, families and classrooms exploring fish and their habitats.

Your tank is waiting.

Start with a blank tank or open the demo scape above. It moves the moment you do.

Start building