Taxonomy of Finfish (1+2)

3.3.3.2 Plotosidae (Stinging catfishes/coral reef catfishes/eel catfishes/barbel eels)

• Elongate body, compressed, tapering to a point posteriorly
• 4 pairs of barbels present with 1 pair nasal, 1 pair maxillary and 2 pairs mental;
• First dorsal fin short-based with a serrated spine and 4-6 soft rays; second dorsal fin (or dorsal procurrent caudal fin), caudal fin and anal fin confluent
• Absence of adipose fin
• Pectoral fins with 1 serrated spine and 9 to 16 soft rays
• A dendritic organ consisting of many vascularised epithelial folds present directly posterior to anus
• Caudal fin rounded or pointed

Eg. Plotosus lineatus

Similar Families

All other catfish families- Dendritic organ absent.  

Ariidae / marine catfishes- Forked caudal fin; adipose fin present; anal and caudal fins not confluent; 3 pairs of barbels present.

Clariidae and Heteropneustidae- Spines in dorsal fin absent.  

Bagridae - Adipose fin present; caudal fin forked; anal and caudal fin not confluent.

Charcidae - Anal and caudal fins not confluent; origin of 2 nd dorsal fin not opposite to pelvic fin origin.