Nyoka-maji hawa ni nyoka wa jenasi Crotaphopeltis katika familia Colubridae. Kuna nyoka-maji katika familia Lamprophiidae pia, jenasi Grayia na Lycodonomorphus. Nyoka hawa sio warefu sana, hadi sm 90 lakini sm 30-60 kwa kawaida. Rangi yao ni nyeusi, kijivu au kahawia lakini tumbo ni kijivunyeupe, njano au machungwa. Spishi moja ina midomo myeupe au njano. Nyoka-maji hukiakia usiku wakiwinda vyura na pengine samaki. Nyoka hawa wana sumu lakini chonge ni nyuma kwa utaya na sumu si hatari kwa watu. Wakitishwa spishi kadhaa hunyoosha kichwa katika pembetatu, kufungua midomo na kufyoa. Hata wanaweza kushambulia. Crotaphopeltis barotseensis, Nyoka-maji wa Barotse (Barotse water snake) Crotaphopeltis braestrupi, Nyoka-maji wa Tana (Tana herald snake) Crotaphopeltis degeni, Nyoka-maji Mbavu-njano (Yellow-flanked snake) Crotaphopeltis hippocrepis, Nyoka-maji Magharibi (Western herald snake) Crotaphopeltis hotamboeia, Nyoka-maji Midomo-myeupe (White-lipped herald snake) Crotaphopeltis tornieri, Nyoka-maji wa Werner (Werner's water snake) Spawls, S., Howell, K., Drewes, R. & Ashe, J. (2002) A field guide to the Reptiles of East Africa.