Common Remora

Overview

The Common Remora is a cosmopolitan marine fish widely recognized for its unique symbiotic relationship with larger marine animals. It utilizes a specialized, oval-shaped suction disc on the top of its head—a modified dorsal fin—to attach firmly to hosts such as sharks, rays, sea turtles, whales, and dolphins. While often seen hitching rides, these fish are capable of free-swimming and are frequently found in tropical and subtropical waters worldwide.

Appearance

This species features an elongated, robust body that is typically uniform in color, ranging from dark grey to brown or black. Its most defining feature is the large, flattened suction disc on its head, which contains a series of transverse, movable plates called laminae that create a vacuum for attachment. The lower jaw projects beyond the upper jaw, and the mouth is lined with small, sharp, inward-curving teeth.

Biology & behavior

Remoras are not considered true parasites; instead, they engage in a commensal relationship where they gain protection, transportation, and access to food without significantly harming the host. They can remain attached to a single host for up to three months but are capable of detaching to move or seek new hosts. They require a constant flow of water over their gills to breathe, which is facilitated by their host's movement or by swimming in currents.

Feeding

The diet of the Common Remora is varied and opportunistic. They feed on parasitic copepods found on their hosts, as well as food scraps left behind by the host's meals. Additionally, they consume small fish, plankton, and even host feces, often darting away from their host to capture these morsels.