News / Species Spotlight / Species Spotlight - Conchfish Astrapogon stellatus (01/12/17)

Species Spotlight - Conchfish Astrapogon stellatus

Species Spotlight - Conchfish Astrapogon stellatus
While it wont be winning any piscine beauty pageants, the Conchfish is a remarkable little species with a truly unique ecological specialization. It belongs to the vast cardinalfish family Apogonidae, but, unlike any other member of this group, the Conchfish has a commensal relationship with the gigantic Queen Conch (Lobatus gigas), hiding in this enormous snails mantle cavity during the day. At night, this fish exits its spacious abode and proceeds to scour the sandy seagrass beds of the Eastern Atlantic for whatever invertebrate morsels it happens upon.

Unfortunately, the Queen Conch has been widely decimated by an unsustainable commercial fishery for its highly regarded meat. Where it was once formerly abundant, this is often now a rarely seen animal, and, in turn, the Conchfish has had to find a new home. Individuals have now been reported from within the Rigid Pen Shell (Atrina rigida), a large burrowing bivalve capable of reaching a foot in length, as well as from unidentified tube sponges, showing that this adaptable species doesnt require the conch to survive. Though it would no doubt be fascinating to keep the two together in an aquarium, the only conch species commonly available are far too small.

But, even when deprived of its snail domicile, the Conchfish will fare just fine in captivity, taking on the usual reclusive lifestyle common to other cardinalfishes. Since this fish leads a mostly solitary existence in the wild, only encountering others of its kind while out foraging, there is no need to keep this species in groups as one would for most other apogonids. And, as one might expect, this cardinalfish is quite hearty and simple to feed, accepting a broad range of foods.

There are two other members of the genus Astrapogon, all limited to the Western Atlantic, from Florida and the Bahamas south to Brazil. The other twothe Bronze Cardinalfish (A. alatus) and the Blackfin Cardinalfish (A. puncticulatus)occur in the same seagrass habitats as the Conchfish, but, unlike their gastropod-loving relative, these species are unknown from living conchs, only being found in the empty shells of dead specimens. While none of these species may be all that beautiful to look at, being dark and diffusely patterned, these fascinating fishes give a wonderful look into how such an unusual interspecies relationship can form.