Fishery of the species Cirrhinus reba is a commercially important freshwater minor carp (minnows) species belongs to the family cyprinidae under the order cypriniformes. It is commonly known as Reba carp. However, in Bangladesh locally known as Raik, Tatkini, Bata, Bhagna while in India and Nepal recognized as Raichang and Striped carp respectively, in Pakistan as Suhnee and Sunee. Roberts. proposed synonym Bangana ariza for this species but was not considered as a valid alternative. The natural distribution of this species is Indian subcontinent. It is widely distributed over India, Bangladesh, Pakistan, Nepal, Myanmar and Thailand. Though, its distribution in Myanmar suggested by Menon but later it is not confirmed again. In India, it is common in the Gangetic belt of the northern region of the country and also in the Cauvery River of the south. Whereas, in Bangladesh is dispersed in the main river systems and all types of water bodies mostly.
Morphology and size C. reba could be identified through their slender body and more slightly more convex dorsal profile than ventral one. Mouth is terminal and snout is slightly projecting, more noticeably in the young fishes. Lips are fleshy, upper lip is fringed in the young, sometimes entire in the adult while a tinny cartilaginous layer is present which shield the lower jaw and possess one pair of barbels. Single short medium dorsal fin with articulated rays originates slightly anterior to the pelvic fin and caudal fin is heterocercal. Cycloid and hexagonal silver scales makes its shiny appearance. However, darkest pigments of scales at the edges forming bluish longitudinal bands above the lateral line.
Minimum and maximum sizes of the species in the whole study period were found 8.4 cm and 23.5 cm respectively. Maximum length of this species reported 60 cm by Hamilton (1822); 22 cm by Bhuiyan [9]; 32.5 cm by Rahman ; 30 cm by Talwar and Jhingran, and 29.3 cm by Hussain.Galib measured highest length (23.5 cm) of this species in 2007 in the Chalan bee1 of Bangladesh.
Sexual dimorphism Male and female C. reba can be differentiated easily by observing the external sexual characters developed in the course of maturation and during breeding season. In males the scales on the flanks, nape and anterior dorsal side are rough with sandy texture while in females scales are smooth. In male dorsal side of pectoral fins at the base is rough, the pectoral fins are slightly stouter and longer while in female they are slightly smaller; males are having stout abdomen with elongated, introvert and whitish vent, on slight pressure on the abdomen prior to vent milt oozes out while females are having bulging abdomen with extrovert, fleshy, round and pinkish vent, on slight pressure eggs come out [13]. Size at sexual maturity of male and female C. reba were estimated as 11.50 cm total length (TL) and 13.50 cm TL, respectively.
Food and feeding habit: Food is the most important and vital need for optimum production of fish. So, the proper knowledge about food and feeding habit and selectivity is a prerequisite for the successful raising of fish. C. reba is a bottom feeder. Its herbivorous feeding habit has been reported by most of the earlier researchers. It feeds mainly on plankton and detritus but also on mud, vegetables, crustaceans and insect larvae. The young one feeds voraciously on zooplankton and grows very quickly, even faster than the young of catla and mrigal. Feed ingredients mainly composed of algae (10%), higher plants (70%), protozoa (5%), crustaceans (10%) and mud and sands (5%). Fry of this species exclusively feed on the animalcules and water fleas; while fingerlings consume in the order of preference the vegetable debris, unicellular algae, detritus and mud. Young ones of this species are used to wonder around the column and the surface waters for feeding.
Habitat and Ecology According to Bhuiyan, C. reba is available in all rivers and clear streams of Bangladesh. Although the fish is rarely available in the eastern part of the country, but it is abundantly available in the western and north western part of Bangladesh. The fish is also found in large streams, rivers, tanks, lakes, reservoirs and inundated fields . Availability of the fish is also recorded in Bookbhara baor, Chalan beel and Halti beel of Bangladesh. It is a bottom dweller and prefers to be in the deeper water. They often migrate at all regions of the water body, especially for the purpose of feeding and breeding. The fry and fingerlings are used to move along the surface and column waters. Breeding Season C. reba is a yearly breeder with a single spawning season limited to south-west monsoons ranging from May to July in Bangladesh and Assam, and June to August in West Bengal with a peak in June [13]. Bhuiyan [9] described in his article from June-September while in another study, Hossain reported breeding season in Bangladesh from June to August.