Betta Fish Tank Setup: What They Actually Need

Bettas get sold in cups and displayed next to unheated 3-litre bowls, and that pairing is the source of most of what people believe about them.

The reason a betta survives a bowl is a labyrinth organ, which lets it gulp atmospheric air at the surface. It's an adaptation to stagnant, oxygen-poor water in rice paddies and slow streams. It means a betta can tolerate conditions that would kill a tetra in a day. Tolerating isn't thriving, and a betta in a bowl typically lives about a year against a proper lifespan of three to five.

The setup

Flow, and why it matters more here

Domestic bettas have been bred for enormous fins, which are heavy and hard to swim against. In the wild the ancestral fish lives in near-still water with short fins.

Put one in a tank with a strong filter and it spends the day fighting the current, gets exhausted, and often ends up wedged behind the decor. Signs of too much flow are obvious once you know: the fish gets pushed around, hides constantly, or its fins are being blown forward while it swims.

A sponge filter run off an air pump solves this properly. It gives you biological filtration with essentially no current.

Cycle it first

The single biggest cause of dead bettas is being added to an uncycled tank. Set up the tank, run it, and grow the bacterial colony before the fish arrives.

That takes three to six weeks fishless, or under two if you can seed the filter with media from an established tank. It's covered properly in the cycling guide, and it's not optional.

Aquascaping for a betta

Bettas rest. They wedge themselves on broad leaves near the surface and sit there, and a tank with nowhere to do that keeps the fish swimming when it wants to stop.

• Broad-leaved plants near the surface: anubias, java fern, or silk equivalents. Real ones also help water quality.
• A cave or two at the bottom for retreat.
• Floating plants to dim the light. Bettas prefer subdued lighting and floating cover makes them noticeably bolder.
• Nothing sharp. Plastic plants with hard edges tear long fins. The test is running a pair of tights over it: if it snags, it'll snag a betta.

Feeding

Bettas are carnivores. A quality betta pellet as the staple, with frozen or live bloodworm and daphnia a couple of times a week. Flake food designed for community fish is largely plant matter and doesn't suit them.

Two or three pellets, twice a day. That looks like nothing and it's correct: a betta's stomach is roughly the size of its eye. Overfeeding causes bloat and constipation, which is one of the most common health problems in the species and is entirely owner-created.

Skip one day a week. It gives the digestive system time to clear and prevents most bloating problems before they start.

Tank mates

One male betta per tank. Two males will fight, frequently to death. This isn't negotiable and it isn't a matter of temperament.

For community tanks, it depends on the individual fish, and some bettas will never tolerate company. If you try, the rules are: nothing with long flowing fins (guppies get attacked as rivals), nothing that nips (avoid tiger barbs entirely), and enough space and cover that everyone can get away. Corydoras and snails are the safest options. Have a backup tank ready before you try.

Sororities of females are frequently recommended online and are genuinely difficult. They need a large, heavily planted tank and constant monitoring, and they fail often. Not a first project.

A heated, filtered, cycled 20-litre tank with plants and a lid runs to about the price of a night out and turns a fish that lives a year into one that lives four. That's the whole argument.