Influence of gut morphology, sensory cues and hunger on feeding behaviour of spangled perch, Leiopotherapon unicolor (Günther, 1859), (Percoidei, Teraponidae)

The morphology of the alimentary canal, feeding technique and responses to sensory cues were investigated in Leiopotherapon unicolor. The small conical teeth on the jaws and pharynx, simple Y-shaped stomach and short gut of L. unicolor are characteristic of opportunistic carnivorous fish. Five types of behaviour, 'basal', 'orientation', 'positioning', 'attack', and'ingestion', were recognised and are described. Capture of prey small enough to swallow whole was assisted by suction created as the mouth opened to engulf prey. Crustaceans too large to ingest whole were broken into smaller pieces against the substrate. Directional and oscillatory movement were the most effective sensory cues in eliciting feeding behaviour, implicating vision as an important sense for L. unicolor feeding in confined aquaria. Acoustic and olfactory senses are less important in prey capture. The frequency with which spangled perch responded to different sensory cues increased with increasing hunger