Dottybacks (Pseudochromidae) are often very colourful, rather hardy and relatively small, typically under 4 inch (10 cm). These fish can be distinguished from other fish by looking at the shape of the eye, see for example the picture of this: Hawkfish, Surgeonfish, Rabbitfish, Angelfish, Triggerfish, Clown/ Damselfish or Pufferfish.
Dottybacks will compete for food with other fish which eat zooplankton off the rocks. Mandarinfish and similar species can find it difficult to get enough food if kept together with Dottybacks.
One could consider the Gramma species, if one wishes a similar fish which is more peaceful.