Sperm whale the line, sparing the whales the need to hunt. However, the amount of fish taken is very little compared to what the sperm whale needs per day. Video footage has been captured of a large male sperm whale "bouncing" a long line, to gain the fish. Sperm whales are believed to prey on the megamouth shark, a rare and large deep-sea species discovered in the 1970s. In one case, three sperm whales were observed attacking or playing with a megamouth. The sharp beak of a consumed squid lodged in the whale's intestine may lead to the production of ambergris, analogous
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