Fins are not just for swimming Fins are great for propelling a fish through water. What’s more, some fins have been specialized to walk, feel, and repel predators. The oyster toadfish has a mildly venomous dorsal spine. Catfish have barbed pectoral fins. The stickleback’s name speaks for itself. Sea robins have pectoral fins that help them walk along the bottom while the pelvic fins of gobies have fused to form a sucker-like disc. A hogchoker’s fringed fins can sense food in the sediment. Many fish use them to attract mates. Other species have fins that serve as a lure to draw prey closer.