Exostoma effrenum Ng & Vidthayanon 2014

Distinguished from its congeners by the following characters: eye diameter 11.5-15.0% HL; head width 18.5-19.8% SL; body depth at anus 10.5-12.4% SL; length of adipose-fin base 25.8-29.0% SL; adipose fin distinctly separate from upper procurrent caudal-fin rays; caudal peduncle length 20.5-21.3% SL, depth 5.1-7.0% SL; caudal fin forked; preanal vertebrae 21-22 (Ref. 97386).

Exostoma effrenum is a species of sisorid catfish from Thailand. This species reaches a length of 6.5 cm (2.6 in).