Monopterus ichthyophoides differs from all other species of synbranchids in having only 2 branchiostegal rays (vs 5–6). It differs further from all other synbranchids, except M. cuchia, M. fossorius, M. indicus, and M. desilvai by the presence of scales. It differs from the latter four species also by the number of vertebrae (79–82 + 34–37 = 114–117 vs M. cuchia 99–112 + 55–70 = 166–188, M. fossorius 73 + 53-56 = 126–129, M. indicus 93–99 + 42–45=137–144, M. desilvai 75 +69 =144). It differs further from M. cuchia in having the scales restricted to the posterior part of its body (vs extending anteriorly up to the head) and from M. desilvai and M. indicus in having scales extending anteriorly far beyond the vent (vs. ending posterior to vent in M. desilvai and M. indicus, but with a small separate scale patch in M. indicus)Ref. 87307).