PLOTOSIDAE Eeltail catfishes (eel catfishes) By Tetsuo Yoshino Plotosus lineatus Medium-sized catfishes mostly less than 40 cm (some exceeding 100 cm) with elongate, tapering body posteriorly. Head and body slimy without scales or bony plates; lateral line complete. Mouth terminal or somewhat inferior with 4 pairs of barbels; 1 pair (nasal barbels) between widely separated anterior and posterior nostrils, 1 pair at corner of mouth, and 2 pairs on lower jaw. Dorsal and pectoral fins with a pungent, serrated and venomous spine at anterior edge; dorsal procurrent caudal fin (DPC, often mistaken as 2nd dorsal fin) and anal fin long, both confluent with caudal fin; adipose fin absent. Dendritic organ present between anus and anal fin. Similar families occurring in the area. Plotosidae different from all other catfish families in having a dendritic organ (marine species), and caudal fin confluent with dorsal procurrent caudal, and anal fins. Ariidae: caudal fin forked; adipose fin present; anal fin short and not confluent with caudal fin; nasal barbell absent. Other freshwater catfish families (Siluridae, Clariidae and Heteropneustidae): dorsal and pectoral fins with no pungent serrated spine at anterior edge; anal fin not confluent with caudal fin. Remarks. Marine and freshwater fishes widely distributed in Indo-Pacific; freshwater species restricted to Australia and New Guinea. Venomous, but marketed fresh and locally important food fishes taken by beach seine and trawl nets.