Refraction of Fishhook barrel cactus blooms in dew drop on a Fishhook barrel cactus thorn. The fishhook barrel cactus typically grows to a diameter of roughly two feet and a height of three to six feet. However, specimens as wide as three feet and tall as ten feet have been recorded.[2] The common name comes from the spines, which are thick and hooked. It has a leathery asparagus green cortex (skin) with approximately 15-28 ribs per cactus. Its flowers are yellow to red-orange and appear atop the cactus fruit during the summer months. The fruits are green when unripe, yellow after the flower dries up, and persist atop the cactus long after the flower is gone, sometimes for more than a year.