Megamouth shark to be the sole extant species in the distinct family Megachasmidae, though suggestion has been made that it may belong in the family Cetorhinidae, of which the basking shark is currently the sole extant member. Researchers have predicted the feeding patterns of megamouth sharks in relation to the other two planktivorous sharks; the three plankivourous sharks have ram feeding in common, as it evolved from ram feeding swimming-type ancestors that developed their filtering mechanism to capture small prey like plankton. In addition to the living "M. pelagios", however, two extinct megamouth species – the Priabonian "M. alisonae" and the Oligocene–Miocene
Feeder fish overcrowded or otherwise sub-optimal environment, they may also carry bacterial infections and parasites, which can be passed along to fish that eat them. A major disadvantage of using feeder fish, particularly goldfish, is that they do not actually simulate what tropical fish eat in the wild. Several fast-growing and hardy species are commonly sold and used as feeder fish. Depending on the locality, feeder fish may include: Although the use of feeder fish is fairly common in the United States, in the United Kingdom it is much less common, with aquarists and hobby magazines in Britain generally rejecting the use