Читать книгу Clinical Guide to Fish Medicine - Группа авторов - Страница 62

This large group of mostly freshwater fish includes several species that are common in the home aquarium or pond including goldfish (Carassius auratus) and common carp (Cyprinus carpio), of which koi are a subspecies (Cyprinus carpio koi). Carp are also important foodfish. Zebrafish (Danio rerio) are common aquarium and research animals. The mouth, jaws, and palate are toothless but there are pharyngeal teeth in most (except algae‐eaters) with a basioccipital grinding pad or “carp stone” on the dorsal pharynx. These stones are shed periodically and are often noted by owners. Algae‐eaters, loaches, and suckers have oral modifications that allow them suck onto rocks and scrape algae. There is no stomach; the esophagus appears to go straight into the intestine. They have a Weberian apparatus. They are physostomous with two‐chambered swim bladders, although many fancy goldfish have lost the caudal lobe (Roberts and Ellis 2012; Nelson et al. 2016; Roberts‐Sweeney 2016).