Common bleak small shellfish and plant detritus. It is found in streams and lakes. The bleak prefers open waters and is found in large numbers where there is an inflow of food from pumping stations or behind weirs. The bleak spawns near the shore in shallow waters. Some are found in deep water. The substrate is not important. The bleak is an important food source for predatory fish. It is more sensitive to pollution than other cyprinids, which might explain the decline in North-Western Europe. Bleak are used as bait for sport-fishing for larger fish. In 1656 in Paris, a Mr. Jaquin
Coconut crab light material will cause the crab to loosen its hold." In the Cook Islands, the coconut crab is known as ' or ', and in the Mariana Islands it is called "ayuyu", and is sometimes associated with "" because of the traditional belief that ancestral spirits can return in the form of animals such as the coconut crab. Coconut crab populations in several areas have declined or become locally extinct due to both habitat loss and human predation. In 1981, it was listed on the IUCN Red List as a vulnerable species, but a lack of biological data caused its