Their gut length intermediates between carnivorous and herbivorous fishes Fig. Care must however be taken to ensure that these food varieties do not carry infections, such as germs or other parasites, in them. The role of bioluminescence in behaviour body part regeneration In regeneration: These are organic substances that act as catalysts for many of the biochemical reactions within the fish. The pancreas is scattered in the mesentery, primarily near the pylorus.
A. Digestive System
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The digestive system The digestive system , in a functional sense, starts at the mouth , with the teeth used to capture prey or collect plant foods. Previous page The skin. Page 6 of 9. Next page The respiratory system. Learn More in these related Britannica articles: Of the approximately species of freshwater fish of the United States, Canada, and Mexico, about 40 have become extinct in the past….
The earliest known vertebrates were jawless fishes of the class Agnatha, and their only living representatives are the cyclostomes—the lampreys and the hagfishes. The modern agnathans retain much of the general organization of the ancestral vertebrates, and, therefore, much of their musculature is…. Similar to other vertebrates, fish have discrete taste and smell systems; however, since they live in water, the taste system is not confined to the oral cavity.
For example, taste buds occur on the lips, the flanks, and the caudal tail fins of some…. The cyclostomes and the elasmobranchs e. There are, nevertheless, two possible ways by which some of these cartilaginous fishes, especially the sharks, react to sounds in the water: Generally meats consist of about 20 percent protein, 20 percent fat, and 60 percent water. More About Fish 68 references found in Britannica articles Assorted References conservation and extinction issues In conservation: Freshwater fish In conservation: In the oceans In conservation: Culture and religion anatomy and physiology bioluminescence In bioluminescence: The role of bioluminescence in behaviour body part regeneration In regeneration: Fishes chemoreception In chemoreception: Fish circulatory system In circulatory system: Circulation in jawed vertebrates excretory system In excretion: Fishes hearing ability In sound reception: Hearing in fishes View More.
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Already read this title? Please accept our apologies for any inconvenience this may cause. Add to Wish List. Toggle navigation Additional Book Information. Description Table of Contents. Inadequate nutrition can result in poor growth, deformities, a depressed immune system, hepatic lipidosis, and impaired metabolism. Iodine deficiency can result in thyroid hyperplasia, which has been seen in both elasmobranchs and teleosts. Hepatic lipidosis is a common problem seen in captive fishes and can occur for multiple reasons.
Examples include starvation, a high percentage of carbohydrates in the diet, a high amount of lipids, and rancidity.
Fish require ascorbic acid, delivered in the feed. Most foodstuffs for fish should be supplemented with a stabilized form of ascorbic acid. Severely affected fish exhibit extreme scoliosis. Feeding a wide variety of feeds is one way to try to meet the nutritional requirements. Live feeds can be varied with diverse commercially prepared feeds. This practice will also help prevent animals from eating only one type of feed.
Fishes that feed at the surface should be fed feeds that float, whereas bottom-dwellers should be fed items that rapidly sink. The feed should be in particles easily ingested by the fish. Flaked feeds may be too large for a small-mouthed fish to easily ingest. Such feeds can be crushed to enable easy ingestion.