Did you know that there are over 30,000 different kinds of fish? Here are some more interesting facts about fish that you might not know:
• Fish are are vertebrates, or animals with backbones.
• They live in water. (A few, however, can survive for months when the rivers they live in dry up. The walking catfish can live for days out of water.)
• They breathe mainly through their gills.
• Fish are cold-blooded. (Their body temperature is the same as the water around them.)
• Fins. Most fish have fins, but not always the same number or the same shape. Fins help fish swim and keep their balance.
• Nostrils. They are not for breathing but for smelling, and some fish can smell well.
• Ears. They are buried deep in their heads
• Gills. Most fish breathe by gulping water and closing their mouths. The water passes over the gills. The blood flowing through carries the oxygen throughout the body. The water flows out the gill slits, which are covered by flaps.
• Eyes. Most fish have one eye on each side of their head. Imagine having your eyes where your ears are! Some fish living in very deep water are blind. Fish do not have eyelids, so they can't close their eyes.
• Scales. Most fish have scales and can tell the age of a fish by looking through a microscope at the rings on the scales, which are added each year.
• Special scales for feeling. Fish feel with a special organ called the lateral line, which runs down the sides of the fish Special scales over the lateral line allow the fish to detect movement in the water nearby.