A small cleaner wrasse works at removing parasites, dead tissue and mucus from a great barracuda. The service they provide is recognized by larger potential predators, which don’t harm these little blue and yellow fish, even when they go inside the mouth to clean.

Great barracudas are generally mostly silver with black marks on the tail fins and second dorsal fins. However, some great barracudas, such as this one, have black marks on other fins and their silvery sides are mottled with darker markings.