Warty Prowfish, Aetapcus maculatus (Günther, 1861)

Introduction

The Warty Prowfish with its distinctive warty skin that can be shed like a snake skin is only found in Australia.

Identification

The Warty Prowfish can be recognised by its warty skin that is regularly shed like a snake skin. Its base colour can be brown, pink, orange, yellow or pale whitish. It often has dark blotches.

This species has a steeply sloping snout and a very long-based dorsal fin. It has large pectoral fins but lacks pelvic fins.

Habitat

It occurs near sponges or algal areas in protected marine waters.

Distribution

The Warty Prowfish is endemic to Australia. It occurs from northern Tasmania to central Western Australia.

The map below shows the Australian distribution of the species based on public sightings and specimens in Australian Museums. Source: Atlas of Living Australia.

Other behaviours and adaptations

Skin-shedding

The skin-shedding process of the species was described by Alison Reynolds in 1979. She described keeping two specimens in an aquarium and observing the skin being shed by the second specimen. She stated that "Because it has not been recorded that these fish shed their skins in such a manner, Rudie wanted to photogaph the whole process. The Prow Fish started to shed its skin quite regularly, once every 22 or 24 days, and typically the days it was due to shed its skin was on a long weekend and Rudie would come home to find a brilliant new skinned Prowie. The 23rd day came around again and the Prowie's skin began to look transparent and fill up with water like a blister - during the night it filled out further and the next morning it looked like a balloon. Eventually the skin split just behind the gills, this enabled the Prowie to fan water out of his gills and push the skin back from his head. Another split along the underside of the jaw and with one big wriggle and a jet of water from his gills, the skin was cast off. I have only heard of two other cases of fish shedding their skins (in the same manner a reptile would), one was a small Pegasus Fish in Guam and the second was a Velvet Fish Rudie found under Portsea Pier. He picked the fish up to relocate it for a photograph and it swam out of his hand leaving behind a complete skin. As this is only a newly observed phenomenon there are no really scientific theories as to why the fish shed their skins in this manner. We believe that because these fish live a rather quiet life spending most of their time either buried in the sand or under or against rocks that a film of bacteria and algae builds up on the skin and consequently the only way to rid themselves of such growths is to shed the whole skin regularly."

References

1. Gomon, M.F. in Gomon, M.F., Glover, C.J.M. & R.H. Kuiter (Eds). 1994. The Fishes of Australia's South Coast. State Print, Adelaide. Pp. 992.
2. Hutchins, B. & R. Swainston. 1986. Sea Fishes of Southern Australia. Complete Field Guide for Anglers and Divers. Swainston Publishing. Pp. 180.
3. Kuiter, R.H. 1996. Guide to Sea Fishes of Australia. New Holland. Pp. 433.
4. Kuiter, R.H. 2000. Coastal Fishes of South-eastern Australia. Gary Allen. Pp. 437.
5. Reynolds, A. 1979. The Warty Prow Fish. Skindiving in Australia. February: 24, 26. (photos by Rudie Kuiter)