Every new aquarium goes through the same invisible process — bacteria slowly building up, ammonia and nitrite rising then falling, the water finding its balance. This simulator lets you watch that happen and make decisions along the way. No experience needed.
Fishless cycling is the gentler option. You add ammonia to feed the bacteria — no fish involved. The bacteria grow at their own pace, and when the cycle is done, the tank is ready for fish.
With a small tank, fishless cycling, and plants — expect the cycle to complete in roughly 3–4 weeks. Ammonia will peak first, then nitrite, then both will fall as bacteria establish. Plants will help keep nitrate manageable.
Once inside, you will see three equipment toggles — heater, filter, and light. They are on by default. Try turning one off to see what happens. There is also a one-time bacteria starter if you want to give things a head start. The log at the bottom explains what is happening as you go.