Bony Fish Anatomy

Bony fish are outfitted with fins that facilitate maneuvering and positioning in the water. The fins, which are made of thin membranes supported by stiff pieces of cartilage, can be folded down or held upright. Fins are named for their location Dorsal fins are on the back, a caudal fin is at the tail, and an anal fin is on the ventral side. Two sets of lateral fins are located on the sides of the fish, the pectoral fins are toward the head, and the pelvic fins are near the tail. The caudal fin moves the fish forward in the water, and the others help change direction and maintain balance. 

Although fish dine on a wide assortment of food, most species are predators whose mouths contain small teeth for grasping prey. Nutrients from digested food are distributed through the body by a system of closed blood vessels. The circulation of blood is powered by a muscular two-chambered 

In many bony fish, some gases in the blood are channeled into another organ, the swim bladder. This organ is essentially a gas bag that helps the fish control its depth by adjusting its buoyancy. A fish can float higher in the water by increasing the volume of gas in the swim bladder. To sink, the fish reduces the amount of gas in the bladder. 

Wooly sculpins spawn all year long, but the peak season is from November to May. The female deposits her eggs in nests where they are fertilized by males. Unlike many other tide pool fish, neither sculpin parent stays behind to guard the eggs, which generally hatch within 13 to 18 days. 

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