The short answer
A 200 litre tank is a proper large community — enough for a real multi-level community or a centrepiece species above several shoals. A balanced plan is three schools of 10–12 fish, a group of 8–10 corydoras, and a centrepiece such as angelfish or a gourami group. This is the size where you can build a full biotope or a lush planted community with room to spare.
Stock by needs, not a formula
The “inch of fish per gallon” rule is unreliable because it ignores adult size, bioload, schooling needs, temperament and filtration. Two hundred litres gives wide scope, but bigger and more numerous fish still produce more waste — so a filter matched to the load and steady maintenance carry the stocking. Plan around adult size and behaviour.
Sensible 200 litre stocking ideas
- A pair of angelfish above 12 neon tetras, 12 harlequin rasboras and 10 bronze corydoras
- A gourami group with two peaceful shoals and a shrimp or snail crew
- A rainbowfish community with an active bottom team
- A planted South American biotope: tetras, corydoras and a dwarf cichlid pair
Keep every schooling species in groups of six or more; larger shoals show their best behaviour in a tank this size. At 200 litres you can also afford generous open swimming space and heavy planting together, which keeps both active and shy species comfortable.
Before you add anything
Always cycle the tank, then add fish in stages so the biofilter matures with the load. Maintain weekly water changes and choose filtration from our aquarium filters hub. For the full picture, read how many fish you can keep and browse the best large aquariums.