Last spring, the Florida Aquarium acquired three baby sea dragons. Right away, veterinarian Ari Fustukjian noticed something was wrong. The frilly fish usually float effortlessly in the water, but these kept sinking. If they spent all their energy trying to stay afloat, the fish would soon die. Luckily, Fustukjian came up with a solution.
Tests showed that the animals didn’t have swim bladders. Fish fill these sacs inside their bodies with air. That air is less dense, or has less matter in a given space, than the surrounding water. The inflated sacs produce an upward force called buoyancy that allows fish to float.
Fustukjian made small rings out of a material that floats in water. Then he tied the rings around the sea dragons. The rings take the place of swim bladders and allow the fish to swim. How are they doing with the floaties? “They’ve adjusted pretty well!” says Fustukjian.