Fancy Goldfish Care Guide: Tank Size, Filtration, and Diet

Fancy goldfish varieties like orandas, ranchu, and bubble eyes are beautiful, long-lived fish, but they’re commonly kept in tanks far too small for their needs.

Tank Size

A single fancy goldfish needs a minimum of 20 gallons, with 10 additional gallons for each additional fish. Goldfish produce a surprisingly large amount of waste for their size, so more water volume means more stable conditions. See our aquarium options.

Filtration

Because of their high bioload, goldfish need robust filtration, often rated for a tank larger than the one they’re actually in. A quality filter and regular water changes are essential to prevent ammonia spikes.

Diet

Goldfish are omnivorous and do best on a varied diet of goldfish-specific pellets, occasional vegetables like blanched peas, and treats such as bloodworms. Avoid exclusively feeding floating pellets to fancy varieties prone to swim bladder issues, as gulping air at the surface can worsen buoyancy problems.

Water Temperature

Goldfish are coldwater fish and generally do best between 65-72°F, making them a poor match for tropical community fish that need much warmer water.

Tank Mates

Stick to other coldwater, similarly-sized fish. Avoid fin-nipping species and fast tropical fish that will outcompete goldfish for food. Browse fancy goldfish varieties like the Panda Butterfly Goldfish.

For background on fancy varieties, see the Wikipedia entry on goldfish.