Microbrachis was an elongated, salamander-like creature, about 15 centimetres (6 in) long, with over 40 vertebrae instead of the average 15-26 in its living relatives. It had minute limbs, and probably swam using fish-like lateral body movements. Microbrachis probably fed on fresh water plankton such as shrimp. Microbrachis was pedomorphic, retaining its larvalgills in adulthood. Similar traits are found in the extant axolotl.