Pardachirus marmoratus

Pardachirus marmoratus, also known as the finless sole, the speckled sole or the Red Sea Moses sole,[1] is a small fish from the Red Sea that secretes an ichthyotoxic milky substance from the base of its dorsal and cloacal fins. This secretion contains pardaxin, a lipophillic peptide that causes severe plasma membrane disruption resulting in cell leakage. The pardaxin containing secretion is used as a defensive mechanism against predators including sharks. Pardaxin is irritating to predator fish, particularly affecting the sensitive gills. Dr. Eugenie Clark conducted much of the early work on Pardachirus marmoratus.[2]

Finless sole
Finless sole, Pardachirus marmoratus
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Pleuronectiformes
Family:	Soleidae
Genus:	Pardachirus
Species:	P. marmoratus
Binomial name
Pardachirus marmoratus (Lacépède, 1802)
Synonyms
Achirus marmoratus Lacepède, 1802 Achirus barbatus Lacepède, 1802 Achirus punctatus Desjardins, 1837

The adult finless soles are bilaterally symmetrical and as they mature their left eye migrates on to the right side of the head. The highly compressed body is convex on the eyed side and flat on the blind side. The rounded caudal fin is not attached to either the dorsal or cloacal fin. It is variable in colour frequently whitish, pale brown to pale grey with a scattering of irregular dark brown ring shape markings and many dark brown spots on the head, body, and fins. long the lateral line, there are normally two brown dots containing yellow flecks.[3]

There is much biotechnological interest in pardaxin, early interest focused on potential shark repellent applications while newer research focuses on antimicrobial and neurotoxic potential of pardaxin and its analogues.[2] One toxin produced, pardaxin-1, does have unusual shark repellent and surfactant properties it created voltage-dependent, ion-permeable channels in membranes and at high concentration it causes lysis in cell membranes. This toxin has been demonstrated to be 5-10 times more toxic, cytolytic and active in the formation of pores in cell membranes than the other toxin exuded, pardaxin-2.[4]

This species is found in shallow, coastal waters where the seabed consists of sand or mud,[1] often near coral reefs,[3] and they feed mainly on benthic invertebrates. It is caught for consumption, despite the poison it exudes and is marketed fresh.[1] They often spend the day buried in the sand with only its eyes and nostrils visible.[3]

It is found in the western Indian Ocean from the Red Sea to Sri Lanka and along the east coast of Africa to Durban.[1]