Fifty-five gallons,
and not a drop of water.
Every scale, fin, gravel grain, plant leaf, bubble and speck of algae on this page is drawn in code. There are no images, no sprites, and no assets of any kind. Nothing is saved. The tank ages while you watch it, the fish grow, the glass slowly greens over, the plants spread, and when you close the tab all of it is gone.
| volume | 55 US gallons (208 L) |
| footprint | 48 x 13 x 21 in, on a matching stand |
| type | Freshwater, planted, community, peaceful |
| photoperiod | 10:00 to 22:00 Central, or whatever you set |
| maintenance | Scrape the glass when you feel like it |
| livestock-losses | None, ever. Nothing here can die |
| persistence | None. No cookies, no storage, no server |
What is in there
Twelve species, all peaceful, chosen because they occupy different parts of the tank and behave differently when food lands. Every individual is generated on load: proportions, fin length, color, patterning, growth rate, and temperament all come out of the same random draw that made the gravel.
Guppies, tetras, danios
The fast ones. Guppies dart in short bursts and reach food before anything else. Neon tetras school properly, holding station with their neighbors rather than merely swimming nearby. Zebra danios cruise the top and will chase each other for no reason at all.
Guppy males get the fan tail and the color, generated as a hue pair with iridescent flecks over it. The females are larger, olive, and considerably more sensible.
Angelfish, bettas, rams, goldfish
The stately ones. Angelfish hold a tall profile and drift rather than swim. Bettas trail unsupported fins a beat behind the body and will flare at anything that crowds them, which lasts about two seconds and settles nothing.
A pair of rams will pick a flat rock, clean it, and hover over it. The betta may build a bubble nest at the surface. Neither leads to anything, which is also true of most real tanks.
Corydoras, clown loaches, kuhlis
The gravel crew. Corydoras shoal along the bottom, sift, and periodically dash to the surface for a gulp of air, which they genuinely do. Clown loaches are playful and will wedge themselves somewhere improbable to rest.
Kuhli loaches spend most of the day hidden in the wood and come out when the light goes off, which is the single most reliable way to tell it is night in a real tank.
Plecos and algae eaters
Armored, deliberate, and usually stuck to something. The pleco and the Chinese algae eater work the front pane, and the algae actually goes away where they have been. Watch the glass over a few minutes and you can see their tracks.
They ignore flake in the water column entirely. Drop a sinking wafer and they will find it.
What it actually simulates
- Personality, per fish. Curious ones come to the front glass when your pointer is near. Shy ones leave. Bold ones use the whole tank, playful ones ride the bubble column, territorial ones claim a spot near a decoration and display at anything that enters it.
- Schooling that is actually schooling. Tetras and danios steer by cohesion, alignment and separation against their own species rather than following a leader, so the shoal has the right nervous, shifting quality.
- Water chemistry that drifts and never punishes. Temperature, pH, hardness, tannins, clarity and nutrients all move slowly and show up visually: tannins warm the water toward tea, clarity hazes it, nutrients green the plants. Nothing you do or fail to do can harm anything.
- Algae with a life cycle. It grows on the front pane in proportion to how long the light has been on, gets grazed off by the pleco and the algae eater, and comes off wherever you drag the scraper.
- Plants that behave like plants. They spread to new spots, pearl visible strings of oxygen from the leaf tips under strong light, shed the occasional leaf which drifts down and darkens the water as it breaks down, and grow greener when the nutrients are up.
- Growth. Every fish is stocked small and grows toward its adult size over the session. Leave the tab open for an hour and the difference is visible.
- A day and a night. The light follows 10:00 to 22:00 Central by default, taken from your own clock. At night the tank drops to moonlight, the top swimmers settle, and the bottom dwellers come out.