Fish - A Large Group of Underwater Creatures

Fish - A Large Group of Underwater Creatures

Fish are cold blooded, it live all the time in water and have fins for swimming. Fish are all vertebrates and have gills for breathe oxygen from the water. Their skin is covered with scales.

Most fish have bone skeletons. some fish, like sharks, dogfish and  rays, have skeletons made of tough gristly cartilage.

Bony fish have a gill slit on either side of their body. The slits are covered with a flap of skin. When the fish opens its mouth, water comes in and washes over the gills.

They absorb oxygen from the water and pass it into the fish's body. The waste water goes out through the slits.

Eels and lampreys are the only fish that have a smooth skin.
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