"On this circle the old man could see the fish's eye and the two gray sucking fish that swam around him."
Remora in the Belize Reef. Note specialized organ (closeup)
Public DomainRemora in the Belize Reef. Note specialized organ (closeup)

These "sucking fish" are small remoras, fish that attach themselves to other fish for purposes of transport and nutrition. Remoras do not eat or harm the host fish; they eat material dropped by the host, the host's feces, and/or bacteria and parasites found on the host. A remora attaches himself to the host not by means of his mouth but by a specially adapted dorsal fin on the top of his head.