Bony Fish | Osteichthyes
Osteichthyes, commonly referred to as the bony fish, is a taxonomic group of fish with skeletons mostly made of bone tissue, rather than cartilage. The group is sorted into two, the ray-finned fish (Actinopterygii) and the lobe-finned fish (Sarcopterygii). All bony fish have gills, and this is the sole means of respiration. Most Osteichthyes are ectothermic (cold blooded), so their body temperature is dependent on that of the water; but some larger marine variations like the opah, swordfish, and tuna, have evolved various levels of endothermy. Bony fish have a variety of diets; they can be carnivores, omnivores, herbivores, filter-feeders, or detritivores.
The largest bony fish is a female Mola alexandrine that was caught on the Japanese coast of Kamogwa, Chiba in 1996. The fish has a total weight of 2,300 kilograms and a height of 2.72 meters. It is currently the heaviest bony fish ever recorded in history.
Bony fish first appeared between 530 to 410 million years ago during the Cambrian explosion. The first bony fish did not have jaws and had a primitive spinal column. It is believed that the first bony fish appeared along with the placoderms, who were the first jawed fish that evolved from their gill arches.
Osteichthyes mostly reproduce through the sperm and eggs that are developed by male and female Osteichthyes. Some Osteichthyes are hermaphrodites and can produce both sperm and eggs. Male and female Osteichthyes may at times look similar or different due to their size, color, head characteristics, and overall body shape.
