Distribution

Tropical to cool coastal waters of the Atlantic and Indo-Pacific. North Sea, Mediterranean, Black and Red Seas, Persian Gulf.

Fig. 4.25 Thalassophryne reticulata.

Biology

Bottom-dwelling marine fishes, some also found in brackish water in river mouths and a long way upstream. The head is wide and flattened, with a large upward-facing mouth. The eyes are also directed upwards. They are excellent at camouflaging themselves by changing colour to blend in with the ocean bottom. They usually hide under stones, seaweed or in hollows or partially bury themselves in loose sediment.

The anterior dorsal fin is small and possesses 2–3 spines. In addition, there is a spine located on each of the gill covers. In some species, the spines contain an internal venom duct and are surrounded by a gland. This type of spine is unique to these fishes. However, it is not certain whether the gland secretions are toxic. Closer examination of Halophryne diemensis, commonly considered venomous, revealed an absence of venom glands and hollow spines (Cameron and Endean 1972). In general there are no known venomous species amongst the Australian toadfishes. When threatened they erect their dorsal fins and gill covers. Accidents are generally the result of treading upon one of these well-camouflaged fish. There have been no reports of active attacks by means of the gill spines, as has been observed with weeverfishes.

Risk

There is little information on accidents with toadfishes. Envenoming (if it is actually possible) appears to be restricted to local symptoms.

Treatment

Symptomatic.

Literature (biological)

Cameron and Endean 1972, Colette 1966, Halstead 1988, Pietsch and Grobeker 1987