Monocentridae

Pinecone fishes are small and unusual fish of the family Monocentridae. The family contains just four species. They live in tropical and subtropical waters of the Indo-Pacific. Pinecone fishes are popular in aquariums, but are expensive and a challenge for the hobbyist.
The pineapplefish, "Cleidopus gloriamaris", is the largest species, reaching up to in length. 
Life history.
Pinecone fishes live in ledges and caves, rocky and coral reefs over a hard bottom. Pinecone fishes are nocturnal.