Results for “reproduction”

Known from the middle and upper Amazon river basins in Brazil, Peru, Ecuador and Colombia. Type locality is 'Amazon River at Obidos, Cudajas, and Tabatinga; Rio Negro, Brazil.' It apparently practises an interesting reproductive strategy in which the eggs are deposited in a shallow depression excavated from the substrate and guarded by the male.

This species is currently the only described member of its genus although colour pattern and morphology vary considerably across its range. You may see reference to this species being the only fish species to possess infra-red vision, but other species also possess this ability and we suspect that infra-red plays an important role in the reproductive cycle of many fishes.

The preciose function of the secondary rostrum remains unknown; some have suggested it may have some hydro-mechanical purpose but it's perhaps more likely related to reproductiion and/or social interactions. Only males develop prominent rostra...

In fact G. farragus and G. ocellatus represent one of 12 pairs of cryptospecies to be found in the genus, differing in subtle aspects of patterning. Cryptospecies are defined as morphologically similar, but reproductively isolated species which in fishes often inhabit adjacent river basins but in some cases occur sympatrically. The phenomenon may be a result of parallel evolution, and is not normally considered to represent an early stage of speciation.

An exceptionally hardy and adaptable species tolerant of a wide range of physiological variables and flexible of diet, factors which have allowed it to become established as an alien species around the globe. Its high reproductive potential and low vulnerability to predation have made it a cause for concern to conservation scientists although as yet there remains no proof of it exerting a negative effect on native fishes in countries outside its natural range.

Retroculus spp. are unsuitable for the standard community aquarium, and should be maintained in a set-up designed to resemble a flowing river. The substrate should be composed of soft sand mixed with small pebbles if the aim is to breed the fish (see 'Reproduction'). Rocks, boulders, roots, branches, and aquatic plants can also be added, although the la...

Bitterlings (see 'Notes') exhibit an unusual spawning symbiosis in which the interlamellar spaces of the paired inner and outer gills of living unionid mussels are used as a spawning substrate. During the reproductive period females develop a long ovipositor which is used to deposit eggs through the mussel’s exhalant siphon. Males then move in to males release milt...