This video shows Rivulus cylindraceus killifish mating.
New Rivulus killi named
Yet another new species of rivulid killifish in the subgenus Melanorivulus has been described, this time from the Paraná River drainage in central Brazil.
Wilson Costa named the new species Rivulus faucireticulatus in the latest issue of Ichthyological Exploration of Freshwaters.
Rivulus faucireticulatus is distinguished from all other Melanorivulus in having a unique colour pattern of a broad sub-basal red stripe on the dorsal fin in males, ventral portion of the head with a black reticulate pattern in females, caudal fin orange in the dorsal and ventral portions and yellow in the middle in females.
Rivulus faucireticulatus is named after the black reticulate colour pattern on the throat of females (from the Latin fauces, meaning throat and reticulatus, meaning with a net-like pattern), and is known only from the type locality in the Claro River (part of the upper Paraná River drainage).
The small ponds that constitute the type locality are in an open area at an altitude of 787 m moderately exposed to sunlight. The water in the ponds was clear, pH 5.5 and at a depth of 1.5 m. All of the adults were collected close to the surface of the ponds, near emerging aquatic plants.