Domino Damsel
A jet-black juvenile marked with three bright white "domino" spots that fade to a sooty grey with age — famously hardy, cheap and forgiving, and famously a bully. Cute as a small fish, but it grows to a stocky 14cm and turns genuinely, fearlessly aggressive, harassing and even killing tankmates many times its size and dominating a community single-handed. Reef- and invert-safe toward corals and shrimp, but keep just one, add it last, and only in a robust, boisterous tank.
Tankmates
How Domino Damsel gets on with the rest of the reef, checked pair by pair by the same engine as the live pre-flight.
Best kept apart
A real clash — aggression, predation or a same-genus fight.
Keep an eye on these
Usually fine, but worth watching in a smaller tank.
Good tankmates
No conflicts — a few popular ones to start with.
