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A fish (pl.: fish or fishes) is an aquatic, anamniotic, gill-bearing vertebrate animal with swimming fins and a hard skull, but lacking limbs with digits. Fish can be grouped into the more basal jawless fish and the more common jawed fish, the latter including all living cartilaginous and bony fish, as well as the extinct placoderms and ...
- Overview
- Structural diversity
A fish is any of approximately 34,000 species of vertebrate animals. The term fish is applied to a variety of vertebrates of several evolutionary lines. It describes a life-form rather than a taxonomic group.
How do fish sleep?
When a fish sleeps, it exists in a seemingly listless state in which the fish maintains its balance but moves slowly. If attacked or disturbed, most fish can dart away. A few kinds of fish lie on the bottom to sleep. Most fish do not have eyelids, so they cannot close their eyes to sleep.
How do fish hear?
The organs of hearing in fish are entirely internal, located within the skull, on each side of the brain, and somewhat behind the eyes. Sound waves, especially those of low frequencies, travel readily through water and impinge directly upon the bones and fluids of the head and body to be transmitted to the hearing organs.
fish, any of approximately 34,000 species of vertebrate animals (phylum Chordata) found in the fresh and salt waters of the world. Living species range from the primitive jawless lampreys and hagfishes through the cartilaginous sharks, skates, and rays to the abundant and diverse bony fishes. Most fish species are cold-blooded; however, one species, the opah (Lampris guttatus), is warm-blooded.
Fishes have been in existence for more than 450 million years, during which time they have evolved repeatedly to fit into almost every conceivable type of aquatic habitat. In a sense, land vertebrates are simply highly modified fishes: when fishes colonized the land habitat, they became tetrapod (four-legged) land vertebrates. The popular conception of a fish as a slippery, streamlined aquatic animal that possesses fins and breathes by gills applies to many fishes, but far more fishes deviate from that conception than conform to it. For example, the body is elongate in many forms and greatly shortened in others; the body is flattened in some (principally in bottom-dwelling fishes) and laterally compressed in many others; the fins may be elaborately extended, forming intricate shapes, or they may be reduced or even lost; and the positions of the mouth, eyes, nostrils, and gill openings vary widely. Air breathers have appeared in several evolutionary lines.
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Many fishes are cryptically coloured and shaped, closely matching their respective environments; others are among the most brilliantly coloured of all organisms, with a wide range of hues, often of striking intensity, on a single individual. The brilliance of pigments may be enhanced by the surface structure of the fish, so that it almost seems to glow. A number of unrelated fishes have actual light-producing organs. Many fishes are able to alter their coloration—some for the purpose of camouflage, others for the enhancement of behavioral signals.
About Fish. All fish share two traits: they live in water and they have a backbone—they are vertebrates. Apart from these similarities, however, many of the species in this group differ markedly...
Jan 3, 2023 · Instead, there are 3 main classes, groups, or types of fish: bony fish (Osteichthyes), jawless fish (Agnatha), and cartilaginous fish (Chondrichthyes). Fish are the most diverse group among vertebrates, with over 33,000 different types of fish species.
- Bony fish, jawless fish and cartilaginous fish.
- The most famous fish is the coelacanth, which has four lobed fins resembling limbs. It is one of the world’s most ancient fish species. Its name me...
- Yes, fish can feel pain, but it is different from the expression of pain from humans. It is difficult to test fish for pain except by looking for u...
- Fish can be predatory, foraging or filter-feeding. Their diets can be carnivorous or omnivorous depending on the species and can include prey from...
- Fish usually breathe through gills, which filters oxygen through water. However, some fish breathe using different means. Lungfish have lungs and m...
- The smallest fish is the cyprinid fish (8mm) and the largest fish is the whale shark (12m).
- “Fish” refers to the singular and one species or to the plural within context. “Fishes” refers to the plural, especially when talking about more th...
- The main differences between the flying fox fish and the Siamese algae eater are color, length and shape, mouth shape, and algae preferences.
- Sword Fish. Swordfish are commonly known as broadbills and are the only species in the Xiphiidae family. They are large predatory fish that migrate as the seasons change.
- Atlantic Cod. The Atlantic Cod is part of the Gadidae family and is primarly hunted for food by humans. It is labeled as vulnerable by the ICUN due to over-fishing for human consumption.
- Mackerel. Mackerel is a common name given to the pelagic fish which comes from the Scombridae family. They are found in tropical and temperate seas around the world and live offshore or along the coast.
- Trout. The Rainbow Trout fish is a species of the Salmonid family and lives in the Pacific Ocean in North America and Asia. It prefers the cold water and usually comes back to fresh water to spawn.
There are more than 800 known freshwater fish species in North America alone. Worldwide, the number is over 10,000 species. Some species of freshwater fish, such as salmon and trout, are called...
Fish (plural: fish or fishes) are a group of animals which live in water and respire (get oxygen) from their gills. As a group, they are much older than other vertebrates. The first fish developed about 500 million years ago. Fish used to be a class of vertebrates. Now the term covers five classes of animals that live in the water: Jawless fish
