The Blue Hamlet (Hypoplectrus gemma) is a tropical fish native to the Western Central Atlantic, including southern Florida, the Florida Keys, and the Bahamas. It is not found outside of this region. The fish is an iridescent blue color with thin dark borders along its tail. It is typically a shy species, preferring to hide among rock work or hover near the substrate.
This fish is not commonly collected by marine aquarists and is rarely found in pet shops. However, it is often available from online sources. The Blue Hamlet is compatible with reef systems but should be watched carefully with small crustaceans. Only one specimen should be kept per tank, as it is aggressive with members of the same species. The Blue Hamlet enjoys a meaty or pellet diet.
In the wild, Hypoplectrus gemma can grow to 13cm and has a minimum population doubling time of less than 15 months.
This species was discovered by Good and Bean in 1882.