The small gold fish with black bars that swims at the nose of a shark, a ray or a big grouper, matching its every turn - that is this species as a juvenile, and it is the reason most divers have photographed one without knowing what it was.
The arrangement is a piggyback. Riding the bow wave of a large animal costs the little fish almost nothing in swimming effort, keeps it under an escort no predator wants to approach, and puts it exactly where prey is flushed out of the sand. It will do this with a nurse shark, a stingray, a turtle, and, given the chance, with a diver.
The adult is a different animal in every way. It loses the gold, the bars fade to a row of dark blotches on silver, and the mouth turns into a rubbery tube it can push out and retract. There are no teeth in it. The fish feeds by plowing into sand and sucking, working out shellfish and buried worms, and a feeding adult leaves a trail of craters.
It reaches 120 cm (4 ft), and large ones travel alone. Same species, two lives, and almost nothing in common between them.
The genus. Gnathanodon Bleeker 1850 - gnathus (jaw) + an- (without) + odon (teeth). ETYFish
The species. Gnathanodon speciosus (Forsskål 1775) - beautiful. ETYFish
- juveniles bright gold with black bars, adults silver with the bars fading to spots
- rubbery protrusible mouth with no teeth in the adult
- juveniles swimming right at the nose or flank of a shark, ray or grouper
- length up to 120 cm
