The frail gourami (Ctenops nobilis) or noble gourami is a mouth brooding species of gourami native to northeastern India and Bangladesh . This species grows to a length of 10cm (00inches). It is only seldom found in the aquarium trade, courtesy of its extreme sensitivity to shipping stress and high levels of aggression.[1] This species is the only known member of its genus.
As these fish grow as juveniles, socialization is shown, but as maturity is reached, then their entire personalities flip upside down with high levels of aggression to others of their kind and potentially other fish as well.
Females of this species have a more slimmer head and jaw shape compared to males. Males have a rounder jaw for mouth brooding (carrying eggs in mouth). The ritual can last for many hours. The female, after laying the eggs, diligently collects every one of them and expels them from her mouth for the male to hold with his anal fin and place in his mouth. They continue this process until every egg is laid and guard the area at the same time. The males are then the parental egg-bearer and gains a cryptic and strange marble patterning. Feeding then is greatly reduced in the male, or ceases altogether. The eggs stay in his mouth for about 7-20 days, after this releases free-swimming fry. This intelligent species shows a learning process in younger or inexperienced individuals in gaining knowledge of how to hold the eggs properly without swallowing them.
These micro-predators live in the clear, overgrown, slow-flowing waters of eastern India, northern Bangladesh, the Sikkim state, west Bengal, Bihar, the Assam states, and just discovered, Nepal. This adaptive species have also been recorded where foliage and vegetation is scarce. during the months of June and July, monsoons are common. Temperatures range from 59-90 degrees Fahrenheit, or 15-32 degrees Celsius, with the cold extremes at the most northerly reaches of its range. Its habitats are subjugated to severe seasonal change with water change, volume, and flow, in which they persevere. At the when living alongside the catfish Pseudolaguvia muricata in Bangladesh the habitat was a slow-moving, shallow stream containing clear water with a substrate of sand and organic detritus. This gourami was recorded here with sympatric species including Barilius barna, B. bendelisis, B. tileo, Devario devario, Oreichthys cosuatis, Psilorhynchus sucatio, Lepidocephalichthys guntea, Acanthocobitis botia, Schistura corica, S. savona, Amblyceps mangois, Mystus bleekeri, Olyra longicaudata, Conta conta, Hara jerdoni, Pseudolaguvia ribeiroi, P. shawi, Aplocheilus panchax, Xenentodon cancila, Microphis deocata, Chanda nama, Pseudambassis baculis, Pseudambassis ranga, Channa gachua, Badis badis, Nandus nandus, Glossogobius giuris, Mastacemelus pancalus and Tetraodon cutcutia.
In the Suthimari River basin, West Bengal frail gouramis were collected in early September in the early afternoon alongside Danio rerio from a habitat containing relatively clear, moderately-flowing water with some suspended sediment and there was no aquatic vegetation present.