Diadem dottyback
Fish
Pictichromis diadema, the bicolor dottyback, diadem dottyback, or purple-top dottyback is a fish species of the dottyback family. It is a popular aquarium fish species. Wikipedia
Scientific name: Pictichromis diadema
Rank: Species
Higher classification: Pseudochromis
Class: Actinopterygii
Family: Pseudochromidae