What is a Fish?

A fish is an animal which lives and breathes in water. All fish are vertebrates (have a backbone) and most breathe through gills and have fins and scales. Fish make up about half of all known vertebrate species.

What is a person who studies fish called : An ichthyologist.

How are fish identified : A combination of the number of fins and their characteristics, scale counts, general features, colour, maximum length and distribution are used.

Difference between male and female fish - In some species the males and females have different shaped bodies or different colouring; in other species there is no visible difference.

How fishes breathe: Some fish have lungs and breathe air, but most breathe through gills. Gills are made up of thin sheets of tissue richly supplied with blood vessels. As water passes over them dissolved oxygen is absorbed into the blood and waste products such as carbon dioxide pass out into the water. The gills are protected by a large bony plate called an operculum.