One betta, done properly
40 × 25 × 30 cm · 30 l
The tank most people actually buy first, kept the way the fish deserves. Thirty litres for one betta is not indulgent — it is the difference between a fish that patrols and a fish that sits.
What the engine says
Using about 6% of the tank's bioload capacity, on weekly 25% water changes. Engine 0.1.2.
The water this tank needs
- Temperature
- 24–28 °C
- pH
- 7–8
- Hardness (GH)
- 6–15 °dH
This is the overlap of every species in it — the narrower it is, the less room you have to drift. Check it against your tap before you buy anything: tap water tool
The stocking
Why it works
A male betta is stocked alone here on purpose. Almost everything sold as a betta tankmate is a compromise in a tank this size: shrimp get hunted, small tetras nip fins, and a second betta is not a discussion. The nerites are the exception — they clear algae, breed nowhere in fresh water, and are armoured enough to be ignored. Heat matters more than it looks: bettas want the upper end of the range, and a 30 litre tank loses temperature fast.
Make it yours
Opens in the planner with the tank and every fish already in place. Change the numbers, swap a species, add your tap water — the verdict updates as you go.
Open this tank in the planner