Adult tripodfish, or triplespines as they are also known for their trio of stiff, sharp rays, are silvery creatures with faint green and yellow markings. Dwelling as they do over exposed shoals of sand or mud, they have no room to hide, unlike their cousins the balistids which can wedge themselves into crevices with the aid of a spiny dorsal fin that is locked into place when a second, shorter spine clicks against the first.
Triacanthids lack this ball-and-socket mechanism, which would have little use away from the rocky overhangs of coral reefs. Instead, these elongated, laterally compressed fish bear three spines, including one particularly long process on their first dorsal fin, and have had their pelvic fins each reduced to a single spike. The lower lobe of the tail, however, consists of soft rays, so the fish is not given to mimic audio-visual accessories in the manner of a deep sea namesake. They are nonetheless benthic animals, scouring the sea bottom for hard-shelled invertebrates which are crushed by jaws armed with twenty heavy incisors.
The spines probably serve to reduce the possibility of getting swallowed by larger pelagics, who would discover the piscine equivalent of a caltrop when they attempt to devour a tripodfish. Younger specimens, such as this incher found at Cyrene Reef, appear to behave like filefishes, moving with trepidation among seagrasses and displaying colours that would shield them from sight until they are big enough to brave the open waters and be a thorn in the flesh of those who would bite before they bark.
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