Matt Clarke looks at an unusual Triportheus species which has recently turned up in imports from South America.
Common name: Giant hatchetfish
Scientific name: Triportheus
Notes: The Triportheus genus was revised in 2004 by Malabarba. It now contains 16 species, with T. orinocensis; T. pantanensis and T. venezuelensis being described in the paper.
Identification: Only three of the 16 Triportheus (T. auritus, T. brachipomus, and T. albus) occur in more than one drainage, so determining the collection locality really narrows down identification. There is a dichotomous key in Malabarba's revision but this is written for each drainage - not handy if you don't know where the fish came from. My checks recorded: 29 branched anal rays; approximately 27 lateral line scales; a pre-dorsal length of 58.5% of SL; a body depth of 31.5% of SL and possibly two scale rows between ventral keel and anal fin origin.
Availability: On sale at Maidenhead Aquatics @ Morden.
Price: A bit dear at 12 each.