There is a sucker on the back. What is the fish that can be sucked on the tortoise's stomach?

1 clean fish with sucker. 2 sucker fish. The sucker fish is named after its first dorsal fin is deformed to form a sucker. This kind of fish is often attached to the bottom of sharks or other big fish, marine fish or ships with suction cups, so that these big animals or ships can take it around the world, so it is called "the laziest marine fish" and "free traveler". 3? Fish? Fish avoid large marine life and can eat their residues; At the same time, it provides cleaning services for big fish. (small? Fish? )