Family: Monocentridae
"A fish that resembles a piece of fruit, now that is something you don't get to see everyday!"
The Pineapplefish (Cleidopus gloriamaris) is a very unusual fish species that has a remarkable resemblance to the Pineapple fruit; hence it's common name. De Vis first described this species in 1882 in his descriptions of some new fish species from Queensland and it is also commonly referred to as the 'Knightfish'. The Pineapplefish is easily recognised by its yellow coloured body with conspicuous black outlines on the scales forming a network pattern similar to that of a pineapple. The scales are very tough and act as armour whilst there is small light organ that can be found on either side of the lower jaw that produces a greenish glow. It is believed that the colour of the light organ changes from green to red as the fish matures. This light organ is best seen at night as it is luminescent and the Pineapplefish uses it to attract small microscopic prey to its mouth to feed on. The Pineapplefish grows to a maximum length of approximately 25 cm.
This species can be found on the east and west coasts of Australia but has not been recorded in Victoria, South Australia or Tasmania. It is generally found inhabiting rocky reefs within estuaries and coastal embayments however some individuals have been trawled in fishing nets from depths of 250 metres. Divers generally see it from depths of 5 to 25 metres. A similar looking species, the 'Japanese Pineapplefish' (Monocentrus japonicus) can also be found in Australian waters however it can be distinguished from the Pineapplefish by its more rounded snout.
The Pineapplefish is generally found in small caves and under ledges where they aggregate in small groups. At the Fly Point divesite in Port Stephens a group of Pineapplefish have been found living under the same ledge for a period of at least 7 years and another colony has been living under a ledge at 25 metres at Halifax Park for approximately 3 years. There are several locations along the New South Wales coast that divers can visit and regularly find Pineapplefish hanging out in the same location for a long period of time. This fish is a very popular species with scuba divers and it can be tricky to photograph as they generally hide in the darkness at the back of a cave or ledge away from the prying lens of a camera! This species is also well-liked by aquarium enthusiasts, as individuals have been recorded for living up to 10 years within private aquariums. Even though this fish resembles a Pineapple it is reported that it is not very good eating!