Learning about classification of fish helps the farmer for getting better production. Different types of fishes are classified in different stages of animal kingdom on the basis of their characteristics, so that we can describe easily various breeds of fish scientifically. Internal relationship of different species and their similarity of an animal is particularly considered while classification. Along with this the purpose of fish classification are identifying a fish, organizing a fish breed to suitable class and indicating ethnic relation of fish with other animals. The difference of fish size and shape is so much that it is very difficult to classify them in different classes and family. As fish has backbone so it is included to chordate phylum. The classification of fish are described below.
According to Nature of Skeleton:
This types of fishes are of two types according to the nature of their skeleton.
- Fish With Cartilage: The fish which has soft skeleton and build by cartilage is known as fish with cartilage. Dog fish, sawfish etc are fish with cartilage.
- Fish With Bone: This types of fish has strong skeleton and well structured with bone. And they are known as fishes with bone. Rui, katla, mrigal etc. are fish with bone.
According to the Presence of Scales: Fishes are of two types on the basis of their accommodation.
- Fish With Scales: The fishes which body is covered with scale is known as fishes with scale. Rui, katla, mrigal, calbasu (kalabaus) etc. are fishes with scale.
- Fish Without Scales: The fishes which has no scale in their body is called fishes without scale. Some fishes without scale are catfish, pabda, tangra, boal etc.
On the Basis of Accommodation: Fishes are of three types on the basis of their accommodation.
- Fish of Freshwater: This types of fish lives in the pond, river, canal, fen etc. with freshwater. Some freshwater fish breeds are rui, katla, mrigal etc.
- Semi Saltwater Fish: This types of fish lives in the estuary and bay with semi saltwater. Tangra, bhetki, gurjali etc. are saltwater fish.
- Saltwater Fish: This types of fishes lives in saltwater. They generally lives in sea and coastal area. Hilsa (ilish), rupchanda, bele etc. are saltwater fish.
The modern scientific classification of fish is described below.
- Kingdom : Animalia
- Phylum : Chordate
- Subphylum : Vertebrate
- Superclass : Nathostomata
- Class : Chondritis