Monkey-faced Prickleback

The species reaches a maximum size of 76 cm (30 in) and may live up to 18–19 years. The heaviest monkeyface prickleback recorded to date was just over 6 lb (2.7 kg). They are slow-growing and reach sexual maturity between four and seven years of age, at a body length of approximately 36 to 45 cm. Some distinguishing characteristics of the C. violaceus include its color, which varies from black to a brownish-green. It also has two uniform dark stripes below its eyes and one or more reddish rust-colored spots on its side or belly. The coloration of both sexes is similar. This species has an anguilliform body shape, with large pectoral fins and two spines on the anal fin. Additionally, breeding males often have a large fleshy lump on the top of their heads.

The monkeyface prickleback has a distribution range from southern Oregon to the northern reaches of the Mexican state of Baja California, this species is a coastal fish that inhabits rocky, intertidal areas close to shore. They are most abundant along the coast of central California. Their vertical distribution ranges from the upper intertidal zone to a depth of 24 meters. However, smaller individuals are commonly found closer to the higher intertidal zones due to reduced predation and competition, where they utilize rocks for protection during low tide. C. violaceus moves from the high intertidal to the shallow subtidal as it grows. It is considered to be a residential species, as it moves short distances from crevices or under rocks to foraging sites. This means it tends to stay in one area and does not move far from its hiding spots. This species appears to occupy a small home range of several meters and is mostly active during periods of a higher tide when it forages.

While young monkeyface prickleback feed on zooplankton and crustaceans, adults are primarily herbivorous, consuming red and green algae. As early juveniles, their prey includes copepods, amphipods, isopods, mysids, and polychaetas. Adults have few predators other than humans, but young fish are vulnerable to piscivorous birds and other fish, such as grass rockfish. Predation primarily affects the earlier life stages of this species; large juveniles and adult fish are most likely to evade or outgrow these predators.