Microbrachis was an elongated, salamander-like creature, about 6 inches 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 larval gills in adulthood. Similar traits are found in the extant axolotl.