Aquarium Simulator - Build a Virtual Fish Tank Online

Aquarium Simulator: Build a Virtual Fish Tank

Aquarium Simulator lets you build and customize a virtual fish tank right in your browser. Add fish, sea creatures, and decorations, then watch them swim with lifelike behaviors — no real tank to clean, nothing to install.

It is made for anyone who wants a calming aquatic scene: relaxation seekers who like watching fish drift, aquarium fans who want to design a dream tank without the maintenance, and anyone after a soothing ambient screen. With the control bar tucked away after a few idle seconds, it doubles as a living screensaver.

Private by design: your aquarium runs entirely in your browser and is saved to local storage on your own device. No creatures, layouts, or settings are ever uploaded to a server.

How to Build Your Aquarium

Open the creature panel

Click the + button in the top-right corner, then pick a tab: Fish, Other (sea creatures), or Decor.

Set the size, then add

Drag the Size slider from 0.5x to 5x to scale new arrivals, then click any creature card to drop it into the tank. Mix sizes for a sense of depth.

Interact with the water

Tap an empty spot to drop food where fish will swim to feed, or hit the Feed button. Tap a fish to startle it, drag any decoration to reposition it, and double-click a creature to remove it.

Set the scene and relax

Use the Theme button to change water color and floor, toggle Sound for ambient audio, and grab a PNG with Screenshot. Your tank auto-saves and returns exactly as you left it.

Features

26 Creatures & Decorations

Choose from 11 fish, 8 sea creatures, and 7 decorations across the Fish, Other, and Decor tabs.

Lifelike Swimming Behaviors

Each species moves in its own way — darting, gliding, drifting, wobbling, or gently floating in place.

Predators & Prey

Swordfish, Barracuda, and Lionfish hunt smaller fish, and nearby prey flee — a living food chain in your tank.

Feed Your Fish

Drop food with the Feed button or by tapping the water, and watch fish swim over to eat it.

Size Control

Scale each new creature from 0.5x to 5x with the size slider for natural-looking depth and variety.

Drag & Arrange Decor

Click and hold any decoration to drag it anywhere inside the tank and lay out your scene exactly how you like.

Themes & Floors

Switch between 4 water colors (Ocean Blue, Deep Sea, Tropical, Night Ocean) and 3 floors (Sand, Gravel, Coral Reef).

Real-Time Water Effects

Rising bubbles, shimmering caustic light, surface waves, and ripples that spread out where you tap.

Ambient Underwater Sound

Toggle a soothing, procedurally generated underwater atmosphere and set the level with the volume slider.

Screenshot & Auto-Save

Save your tank as a PNG image, and your whole aquarium is auto-saved to your browser between visits.

Frequently Asked Questions

Is the aquarium simulator free, and do I need to download anything?

Yes, it is free and runs in your browser. There is nothing to install and no sign-up — open the page and start adding fish.

How many creatures can I add?

You can have up to 100 items in the tank at once, counting fish, sea creatures, and decorations together. The counter in the bottom-right shows the current total.

How do I feed the fish?

Click the Feed button to drop food from above, or tap any empty patch of water to drop food right there. Nearby non-predator fish will swim over to eat it.

Can I move or remove a creature?

Click and hold (or long-press on mobile) a decoration to drag it around the tank. To delete one item, double-click it; to empty the whole tank, use the Clear All (trash) button in the control bar.

Does the size slider change fish that are already in the tank?

No. The size slider only sets the scale of newly added creatures. Anything already swimming keeps its original size.

Can I use it as a screensaver or on a TV?

Yes. The control bar fades away after a few idle seconds, leaving a clean, full-screen underwater scene that works well as an ambient screensaver on a monitor or a big screen. It is fully responsive, so it also works on phones and tablets.

Is my aquarium saved, and is any data sent to a server?

Your tank — every creature, position, decoration, and theme setting — is saved to your browser's local storage and restored when you return. Nothing is uploaded; all of it stays only on your device.