Whalesucker

About

The whalesucker (Remora australis) is one of the more unusual fish you'll ever encounter in the saltwater world, and keeping one in captivity is essentially a project for institutions rather than home hobbyists. In the wild, this species spends its life in the open ocean attached to cetaceans, primarily whales and dolphins, using a highly modified dorsal fin that functions as a powerful adhesive disc. The relationship is generally considered commensal: the whalesucker gets a free ride, a meal of scraps and parasites, and protection, while the host appears largely unaffected. Found throughout tropical and subtropical seas, it can grow to a respectable length and has a streamlined, muscular body built for life in fast-moving pelagic water. In captivity, the practical challenges are immense. A tank of at least a thousand gallons is the starting point, and that doesn't solve the deeper problem. This fish is psychologically and physiologically adapted to life attached to a large moving host. Even expert-level marine hobbyists rarely attempt to keep remoras long-term, and the whalesucker's specialization makes it arguably the most impractical species in this entire family. Fascinating to observe in the wild, but best appreciated there.