STUDY OF FISHES OF NEPAL.

Nepal have different fish species and Following fish species are discussed over here under different categories:

1. Labeo rohita
2. Cirrhina mrigala
3. Catla catla
4. Clarias batrachus
5. Heteropneustes fossilis

Almost all fishes found in Nepal are eaten by local people who believe that the scaly fishes are delicious. Asala is regarded as most delicious among the carp fishes of Nepal.

1. Rohu (Labeo rohita):

Rohu is considered the tastiest among the cultivated carps in Nepal. It is characterized by an elongated and cylindrical body, small or pointed head, sub-terminal mouth and one pair of small maxillary barbells. The lips are thick and fringed. The body color is dull, reddish on the sides and whitish on belly. Rohu is bottom and column feeder (browser), feeds on plant matter including decaying vegetation. Foods of this fish includes planktonic and filamentous algae, periphyton, rotting vegetation, detritus and a small proportion of crustaceans and rotifers. Growth is slow in the first year (up to 900 g), largest size attained is 1m and 30 kg. Sexual maturity is attained towards the end of the second year. Rohu is seasonal breeder and artificial breeding is done by hypophysation. The breeding season is June to August when the temperature is 25-30⁰ C.

2. Catla/Bhakur (Catla catla):

Catla is a fast a fast growing fish among the indigenous cultivated carps. It has deep, laterally compressed body with massive head and large upturned mouth. The barbells are absent and lips are non-fringed. Body color is grayish to silvery on upper sides and whitish on belly. It is a surface, zooplankton feeder but young ones feed both zooplankton and phytoplankton. Catla grows to over 1.5 m length and size of 45 kg. Its growth in the first year is 1-1.5 kg. Time to maturity and breeding behavior is similar to rohu.

3. Mrigal/Naini (Cirrhinus mrigala):

Among indigenous fish mrigal is next in importance to rohu and catla for culture. This fish is characterized by elongated and cylindrical body, small head and sub-terminal mouth with thin non-fringed lips. One pairs of small barbells are present. The upper jaw is longer than the lower jaw. The body color is grayish on dorsal side and whitish on belly, but is not pinkish as rohu. Mrigal is a bottom feeder, omnivorous and feeds on detritus, mud organisms, decaying plant and animal matter, however, young ones feed on zooplankton. Mrigal grows slower than catla and rohu. Largest size attains is 90 cm and 30 kg. Time to maturity and breeding behavior is similar to rohu and catla.

4. Common carp (Cyprinus carpio):

Common carp is characterized by a flat and deep body, short and small head, protractile mouth and two pairs of maxillary barbells. The dorsal fin is long with a sharp spine. It is a bottom feeder, omnivorous and feeds on insect larvae, worms, molluscs, detritus, fresh and decayed vegetation and accepts artificial feed also.Common carp is a multiple breeder and can breed upto 5 times a year.

5. Grass carp (Ctenopharyngodon idella):

The body of grass carp is elongated and cylindrical with large greenish scales. Head broad, barbells absent and mouth sub-terminal with upper jaw slightly longer than the lower jaw. It has a toothless mouth, but has specialized pharyngeal teeth for grasping aquatic vegetation. Gill rakers are short and sparse. Grass carp is a column/marginal feeder, herbivorous and feed on a wide variety of aquatic macro vegetation including certain terrestrial plants. It is a voracious feeder and can consume 50-60% weight of grass per day of its body weight. But the digestion of this fish is said to be incomplete and  about half the food material ingested is excreted as feces. It is one of the fast growing fish and attains 1-2 kg in the 1^st year.

6. Silver carp (Hypophthalmichthys molitrix):

This fish is characterized by the flat and laterally compressed body covered by by small silvery scales. Head small, barbells absent, mouth upturned with lower jaw longer than upper and the abdominal keel is complete. The posterior margin of the pectoral fin does not extend beyond the base of the pelvic fin as in bighead carp. Gill rackers are dense, interlaced, connected and covered with a spongy sieve membrane. It is a surface, zooplankton feeder but young fry feed on zooplankton such as rotifers and nauplius larvae. It grows 1-2 kg in the 1^st year and attains largest size of 40-50 kg.

7. Bighead carp (Aristichthys nobilis):

The body of this fish is flat, laterally compressed and covered by small silvery scales brownish above. Head long and massive, barbells absent, mouth large, upturned with lower jaw longer than upper and abdominal keel is incomplete. The posterior margin of the pectoral fin extends beyond the base of the pelvic fin. It is a surface, zooplankton feeder but larvae mainly feed on unicellular phytoplankton, rotifers and nauplii. It grows 1-2 kg in the 1^st year and attains largest size of 40-50 kg. It is a seasonal breeder, matured in 2-3 years and artificial breeding is done by hypophysation. This is a docile and hardy fish for transportation and handling.

8.Gardi (Labeo dero):

It is the indigenous cold water fish species of Nepal. Gardi is considered tasty among the domesticated fish species in Nepal. It is characterized by elongated and cylindrical body, small and pointed head, sub-terminal mouth and one pair of maxillary barbells. The lips are thick and fringed. The body color is dull blackish on the sides and whitish on belly. The hill stream is the best for its survival.

9. Sahar (Tor tor):

It is stout fish with a deep body and dorsal side more convex having head length shorter than body depth or snout is less pointed than Tor putitora. It has small mouth narrow gapes and maxillary barbells are larger than rostal barbells. It is omnivorous, body color dark grey with grayish along upper half of the body and sides and slightly golden. Its abdomen is silvery white with golden color. Maximum size attained 1.5 m.

10. Sahar/mahaseer (Tor putitora):

It is also known as slim bodied mahaseer has slender body having head length greater than the depth of the body and snout pointed. The male fish has enlarged lips with two pairs of barbells of equal length. It is also omnivorous. The body color is olive green on the back, silvery on the belly and pinkish on the side. The largest size attained 2.7 m.

11. Katle (Neolisochilus hexagonolepis):

It is well known colorful game fish of Nepal. The body is olive green dorsally and splashes of golden on sides. There is yellow band just above the lateral  line. Fins are slaty grey, fant towards the  margin. Scales are hexagonal in shape and omnivorous in nature.