Pricklebacks (family Stichaeidae) are long, compressed, and somewhat eel-like fishes with a long dorsal fin that is sometimes joined to the caudal (tail) fin. The name “prickleback” is derived from the fact that in most species all the rays in the dorsal fin are spinous. The Crisscross Prickleback (Plagiogrammus hopkinsii) is found in the eastern Pacific off central and southern California (U.S.A.). It occurs in rocky intertidal areas and out to a depth of around 21 m. These fish have two lateral lines that branch vertically to form platelike divisions on the sides of the body (these platelike divisions are not present in similar species in California). Crisscross Pricklebacks are nearly uniform blackish to dusky brown, with dusky fins and a dark stripe behind the eye. They may reach a maximum length of ~20 cm. (Eschmeyer and Herald 1983)

According to Fitch and Lavenberg (1975), Crisscross Pricklebacks inhabit rocky stretches along California’s outer coast where there is dense algal cover. Spawning is believed to occur in spring and summer. It appears that some individuals are sexually mature at two years and all at three years, when they are around 10 cm long. A 16 cm individual weighed about 35 g and was six years old. Based on these growth data, Fitch and Lavenberg estimated a maximum lifespan of less than 10 years. Examination of stomach contents revealed that these fish feed on a wide range of invertebrates, but especially crustaceans (mysids, amphipods, and shrimps) and mollusks (chiton remains) (Fitch and Lavenberg 1975). The specific epithet “hopkinsii” honors Timothy Hopkins, founder of the Seaside Laboratory at Pacific Grove (now Hopkins Marine Station, Stanford University’s marine laboratory). (Jordan and Evermann 1900; Fitch and Lavenberg 1975)