Goldfish

Tankmates: Best with other goldfish of similar build: keep slow fancy breeds apart from fast single-tailed goldfish and koi, which outcompete them. Tropical community fish need different temperatures, and anything small enough to swallow (fry, shrimp, small snails) will be eaten. Large snails such as mystery snails are usually tolerated.

Feeding: Sinking or pre-soaked foods reduce air gulping in round-bodied breeds. Overfeeding causes bloat and fouls water quickly.