Time up fish3/10/2023 The eyes are rounder in fish than mammals because of the refractive index of water and focus is achieved by moving the lens in and out, not reshaping the lens as in mammals. Water is "inhaled" through the mouth, passes over the gills and is "exhaled" from beneath the operculum.įish can detect color. An operculum (gill cover) that is a flexible bony plate that protects the sensitive gills. The gills are the breathing apparatus of fish and are highly vascularized giving them their bright red cover. Rays are less rigid and frequently branched. The soft dorsal and caudal fins are composed of rays, as are portions of other fins. Catfish have notably hard sharp fins, of which anglers should be wary. In many freshwater fishes the fins are supported by spines that are rigid and may be quite sharp thus playing a defensive role. Anglers should be careful not to rub this "slime" off when handling a fish that is to be released. Most fishes also have a very important mucus layer covering the body that helps prevent infection. Bass and most other fish with spines have ctenoid scales composed of connective tissue covered with calcium. Ctenoid scales have jagged edges and cycloid ones have smooth rounded edges. Scales in most bony fishes (most freshwater fishes other than gar that have ganoid scales, and catfish which have no scales) are either ctenoid or cycloid. The paired fins assist with steering, stopping and hovering. The caudal fin is the main fin for propulsion to move the fish forward. The dorsal and anal fins primarily help fish to not roll over onto their sides. Fishes such as catfish have another fleshy lobe behind the dorsal fin, called an adipose (fat) fin that is not illustrated here. They are either single fins along the centerline of the fish, such as the dorsal (back) fins, caudal (tail) fin and anal fin, or paired fins, which include the pectoral (chest) and pelvic (hip) fins. The largemouth bass illustrated above has the typical torpedo-like (fusiform) shape associated with many fishes.įins are appendages used by the fish to maintain its position, move, steer and stop. Approximately, 22,000 species of fish began evolving 480 million years ago. Most fish have scales and breathe with gills. The following illustration of a largemouth bass shows some of the common external features that are used to describe the differences between fish that are explained in more detail below.įish are animals that are cold-blooded, have fins and a backbone. Florida Youth Conservation Centers Network.Great Florida Birding and Wildlife Trail.Report injured, orphaned or dead manatees.
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