They have what is called a nictitating membrane, which is a tough membrane that protects the eyes from the bones and debris that may cut into their eyes as they are feeding. Do fish have eyelids? Actually most fish do not have eyelids, but sharks do. What do we have that protects our eyes and keep them moist, so they do not dry out-eyelids. Fins are used for steering and movement.Įyes: Fish have eyes, which enables them to see well underwater. Fins help the fish move through the water. Other sharks are able to pump water over their gills and rest on the ocean bottom such as the White tip reef shark, the lemon shark and the nurse shark.Ħ.ğins: All fish have fins. Many sharks have to constantly swim around and move in order to keep the flow of oxygen running through their gill slits. Sharks do not have swim bladders however. The fish is also able to deflate its swim bladder to sink to deeper depths. It is able to take air from its bloodstream to fill up the air bladder. Swim Bladder: The swim bladder of a fish looks like a small balloon which helps the fish to control its buoyancy or ability to float and move up and down within the water. Because sharks are cartilaginous, this means that they do not have any bones in their body, except for their jaws.ĥ. Sharks are cartilaginous fish that have backbones made out of cartilage-that tough flexible material that makes up our ears and parts of our nose. Fish too have backbones so that makes fish vertebrates. Vertebrate: The presence of a backbone makes an animal a vertebrate. So, which fish would have the colder body temperature… a fish living in Hawaii, or Alaska? Right, the fish living in Alaska probably would have the colder body temperature because the water is colder.Ĥ. Because fish are cold-blooded, their body temperature changes with their surrounding environment. We are warm-blooded, which means that our bodies stay at a constant temperature of about 98.6 degrees. There are rings on the scales of fish which show the growth of the fish, which enable us to estimate the age of the fish.ģ.Ĝold-blooded: Fish are cold-blooded unlike us, mammals. The concept is similar to counting the rings of a tree trunk to see how old it was. You can actually tell the age of a fish by looking at its scales. Every fishes scale is unique to that species so, if you were to find some fish scales, you would be able to tell what kind of fish it was, just by examining the scales. The scales also make the fish more slippery and slimy, which makes them more streamlined and difficult to catch. This provides protection like a flexible suit of armor. Scales cover the body, overlapping, kind of like shingles on a roof. Scales: Scales provide protection for the fish against diseases and infections and some predators. The gills take the oxygen out of the water and bring it into the body of the fish.Ģ. Gills: In order to breathe, we use our lungs to bring oxygen into our bodies.

Does a shark have a backbone