The Knight fish are widely distributed throughout Australian waters from Shark Bay, WA to the Capricorn Group, QLD. Adults inhabit deep water to 250 metres and juveniles are found in comparatively shallow water in caves on reefs and occasionally enter estuaries. The knight fish grows to a maximum length of 22 centimetres.
The Knight fish has a distinctly rounded, armoured body covered in yellow plate-like scales, each of which has a pointed ridge and are edged in black. The have large eyes, and small fins making them not very efficient swimmers. Their first dorsal fin is reduced to four strong, membrane-free spines. They have a red luminescent organ on the lower jaw, which harbours light emitting- bacteria. The green light produced by this phosphorescent bacteria is used at night when they move out over open sand to hunt shrimps and other invertebrates which are attracted to the light. During the day the knight fish hide in caves, under ledges of rocky coastal reefs, singly or in small groups.
Other common names include Pineapple fish, Luminescent Pineconefish, Pinecone Fish, Port and Starboard Bightfish, Port and Starboard Light Fish
Occurrence at the Busselton Jetty
The Knight fish leads a fairly cryptic and nocturnal existence and therefore are only rarely observed from the Underwater Observatory. However, they are often encountered under fallen timber piles or inside old eroded piles on the seafloor by divers in small groups of two to three.
Image by: Busselton Jetty Inc.