Aquarium Simulator Online

A living 3D fish tank in your browser. Feed it 6 pinches a day and watch every fish grow from a tiny fry into a full-grown adult — free, no sign-up, no ads, nothing to lose.

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Features

Fish grow as they eat

Every pellet a fish swallows is remembered for that individual fish. It grows from 46% of adult size up to 122%, passing three visible stages — fry, young, full-grown — with a celebration at each one.

6 pinches of food a day

The daily food counter sits in the corner. Each tap on the water, or on the food button, spends one of the six pinches. It refills on its own at local midnight, so raising the tank stays a small daily habit.

No hunger, no death, no penalty

Progress only ever goes up. Skip a day or skip a month — nothing starves, nothing shrinks, nothing dies. The tank simply waits exactly where you left it.

Five species that grow at their own pace

Small blue tetras fill up after 10 pellets, clownfish after 15, yellow tangs 18, long-finned bettas 20, and the big bottom-cruiser needs 30. Big fish eat more and grow slower, just like real ones.

Believable underwater light

Vertical water gradient, depth fog, drifting light beams and animated caustics rippling across the sand and over the fish themselves — all generated in code, no image files.

Real schooling behaviour

Fish separate, align and group like a real school, bend their whole body into a turn, pulse forward with every tail beat, and glide smoothly away from the glass instead of bouncing off it.

Day, night and fullscreen

Switch to a cool blue night scene with dimmer beams and slower fish, or go fullscreen for a wall-sized tank. Your choice is remembered.

Your tank stays on your device

Growth progress and the daily food count are saved in your own browser only. Nothing is uploaded, no account exists, and clearing browser data simply starts a fresh tank.

How to Use

1

Open the tank

The aquarium fills the screen straight away — no account, no download, nothing to configure. Use the fullscreen button in the corner for a wall-sized view.

2

Move your pointer to attract fish

Slide your mouse or finger across the water. Small fish get curious and swim towards it; the big bottom fish keeps its distance. This costs no food.

3

Spend a pinch of food

Tap anywhere in the water, or tap the 🍤 button, to scatter 8–12 pellets with a ripple. That is one of your six daily pinches. Aim where the fish already are — pellets that reach the sand uneaten fade away.

4

Watch them grow

Each fish that swallows a pellet swells a little and keeps the gain forever. The capsule in the corner shows the tank's average growth, and a badge and a chime mark every fish that crosses into a new stage.

5

Come back tomorrow

Once the counter reads 0/6 the fish stop being fed for the day — nothing bad happens, they just carry on swimming. Six fresh pinches appear after local midnight.

Frequently Asked Questions

How does the growth system work?
Every pellet eaten is counted for that individual fish. A fish starts at 46% of its adult size and reaches 122% once it has eaten its species' full quota — 10 pellets for a small tetra, up to 30 for the big bottom-cruiser. Growth is smooth and permanent, and each fish passes three visible stages on the way.
Why can I only feed 6 times a day?
The daily limit is what gives the tank a rhythm: a few pinches, then let it run. It keeps raising the fish a small daily habit instead of something you rush through in one sitting. The counter resets at midnight in your own time zone.
What happens if I do not feed them for a while?
Nothing at all. There is no hunger meter, no illness and no death. Fish never shrink and never lose progress — a tank left alone for a month is exactly as grown as you left it.
Does one tap really count as a whole pinch?
Yes. A single tap scatters 8–12 pellets and spends one of the six. Pellets that reach the sand without being eaten fade away, so dropping food into a crowd of fish gets far more out of each pinch than dropping it into empty water.
Can I start over?
Yes — the reset button turns every fish back into a tiny fry after a confirmation. Note that today's remaining food is not refunded, so a reset is best done on a fresh day.
Is my progress saved, and is any data collected?
Growth and the daily food count are stored in your own browser's local storage. Nothing is uploaded and there is no account, so the tank does not follow you to another device and does not survive clearing your browser data.
Is this a tool with a score?
No. There is no score, no timer, no failure state and no ending. Growing the fish is the only progression, and it is designed to be watched rather than won.
Can I use it as a screensaver or background?
Yes, that is what it is designed for. Go fullscreen and the tank fills the display; the interface is tiny and stays out of the way.
Does it need any downloads or plugins?
No. It runs entirely in your browser using WebGL. If your device does not support WebGL, a simplified 2D aquarium is shown instead — with the same feeding and growth rules.
Will it slow down my computer or phone?
The fish count adapts to your device, and if the frame rate drops the simulation quietly reduces the number of fish to stay smooth.

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