60 × 30 × 33 cm · 44 L · Walstad, no filter, no cleaning
A 60 cm low-tech planted tank — Walstad method: an inch of mineralised soil under a sand cap, low light, no CO₂ injection, no filter, no water changes. It is meant to be left alone and watched.
Nothing here is a goal. Feed it and populations rise until the plants pull the nitrate back down; trim it and light reaches the leaves underneath. Everything else happens on its own schedule.
| Click | Select any organism — fish, shrimp, snail, or a hover of micro-life — to read its name, role, age and generation. |
| F | Feed a pinch. Uneaten food becomes detritus; ammonia and nitrate follow. |
| T | Trim. Drag across the tank to cut plants back; light then reaches what was beneath them. |
| C L | Cycle view (chemistry, gas exchange, populations) and the journal. |
| H | Hide the controls for ambient viewing; move the pointer or tap to bring them back. |
| Space | Pause. + / − change speed. |
| Esc | Close panels and deselect. |
At 1× the tank follows your own clock, lights on at 10:00 and off at 19:00. Speeding up runs the ecology faster; a day per second shows a season go by. The tank keeps its own calendar when you close the tab and catches up when you return.
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Offspring inherit shuffled parental genes with a little mutation, so finnage, size, boldness, shell colour and that deep cherry red all drift from generation to generation.