Fish-Eating Anemone

Urticina piscivora is a large anemone, growing to a maximum height of around 20 cm (8 in) and 10 cm (4 in) in diameter. The column is bright red in colour. The acontia is absent, but it has tubercles. These are not white and are arranged in circumferential rows. Normally they do not accumulate debris such as shells and sand.

This species occurs from Alaska in the north, down to La Jolla, California in the south.

As its name suggests, this species is capable of capturing and consuming small fishes and shrimp. It does so through the use of its tentacles, stinging its prey with a potent toxin containing Upl protein which paralyzes them. However, Oxylebius pictus (the painted greenling) and Lebbeus grandimanus (candy stripe shrimp) have the ability to remain among the tentacles without being harmed. Their sting can also be severely painful for humans.

Unlike other sea anemone which are mostly sessile, Urticina piscivora has the ability to detach quickly and reposition itself when it feels threatened by a predatory starfish. Since this anemone is unable to actively swim once detached it is deposited elsewhere by the currents.

Many species of anemone are monoecious, meaning that each individual organism contains both the male and female reproductive organs of the species. The fish eating anemone on the other hand is dioecious, meaning that it has distinct male and female individual organisms. They reproduce sexually through the external fertilization of egg and sperm. The produced larvae will float in the current until it eventually lands. Afterwards the larvae will attach itself to the bottom develop a pedal disk which will grow to form an anemone.