Monocle Bream

One species here, in all three tiers: the gold two-line monocle bream, Scolopsis bilineata. It works the edge where sand meets rubble, taking small crustaceans and worms, and it stays calm with fish its own size. A sensible choice for a fish-only tank with a real sand bed rather than a bare bottom.

It hunts small invertebrates, so a cleanup crew of tiny hermits, snails and shrimp will thin out around it. The juvenile’s black-and-white banding fades as it grows into the plainer adult with the gold stripe, which catches people out. Buy it for the adult it becomes, and give it open water to cover.