Phalloceros enneaktinos, the nine ray toothcarp, is a species of poeciliid fish native to Brazil.
Phalloceros enneaktinos is found in Brazil and is known only from where the type localityis located in the Córrego da Toca do Boi, Rio de Janeiro, Brazil.
The females of this species grow to a total length of , while males remain smaller at . .
The fish live in tropical freshwater; and are pelagic.
The fish is named in Latin = enneas meaning nine; aktinos, rays, referring to number of the dorsal-fin rays in both sexes.