Tool use by a temperate wrasse, California sheephead Semicossyphus pulcher.

Multiple individuals of a temperate reef fish species (California sheephead Semicossyphus pulcher) were observed using an anvil to crush hard-bodied invertebrate prey. Potential implications for this behaviour extend from individuals, which may experience reduced likelihood of injury and increased reproduction, to communities, which could see changes in prey abundance and size-distribution, with particularly important consequences for communities regulated by top-down processes. Until relatively recently, the use of simple tools by fishes was overlooked compared with observations of tool use by primates and birds; however, observations of tool use, and interesting foraging behaviours in general, by aquatic organisms should increase with improved underwater monitoring technology.