EVERYDAY SCIENCE

Detailed explanation-1: -A fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most jawed fishes is covered with these protective scales, which can also provide effective camouflage through the use of reflection and colouration, as well as possible hydrodynamic advantages.

Detailed explanation-2: -Many fish have an outer covering of scales. Scales protect fish, much like a suit of armor. All fish have a slimy covering of mucus. This substance allows the fish to swim through the water with very little drag and also makes it difficult for other organism to attach to the fish.

Detailed explanation-3: -Cyclostomes have no scales. Cyclostomes are vertebrates that have cranium enclosing the brain. E.g. Lamprey, Hagfish. The living aquaculture systems are the cyclostomes, which are primitive in many ways but specialized in others.

Detailed explanation-4: -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.

Detailed explanation-5: -Fishes that lack scales have other layers of protective material over the skin. They have bony plates over the skin and contain an additional layer of teeth-like protrusions over their skin. Jawless fishes, eels, catfish, and mandarin fish lack scales on their body.