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: Labracinus cyclophthalmus.
They can be quite aggressive towards other fish, if they are kept together with more docile species or if there is not enough space. They are especially aggressive towards fish that resemble themselves or Wrasses, as in the wild, Wrasses will go after their eggs.
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.