In science of Biology the term fish is stringently used for the creatures with a backbone which has gills lifelong and limbs.
The word fish is a collective term which describes all the species of fishes. The stringent biological term for fish is finfish to differentiate from aquatic organisms which are accumulated in fisheries or aquaculture.
There are several types of fishes exists in the world of water which can be salt water fish, fresh water fish, farmed or wild fishes.
Fishes are mainly used for their commercial value. They are also used for Recreational & Substantial fishing purpose.
Now-a-days considerable researches are being conducted globally which has a great value.