Outwardly, Homaloptera tweediei resembles Homaloptera smithi, its close relative, but is distinguished by its smaller size — adults grow up to 4 cm. A distinctive feature is the fish's elongated body. Large paired fins are shifted towards the belly and positioned horizontally, allowing the fish to firmly cling to the surface of stones or snags, successfully resisting strong currents. Its coloration is gray, adorned with four dark, irregularly shaped spots. Sexual dimorphism is weakly expressed, and there are no obvious external differences between males and females.