An angelfish at the Denver Zoo was "swimming abnormally." A special CT scan revealed the reason why.

A fancy-looking French angelfish that was found one day with a funny float has its buoyancy back after taking some time from its tropical trappings to get a CT scan at the Denver Zoo.

A zoo worker recently noticed the blue and yellow fish was "experiencing buoyancy issues and swimming abnormally" with a tilt, the zoo said. That prompted a visit last week to the facility's on-site hospital for an ultrasound and the CT scan.

The CT scan took place in a machine large enough to fit a 700-pound grizzly bear, so some special accommodations were required, zoo spokesperson Jake Kubie said. The approximately seven-inch fish was sedated, balanced upright on a sponge and had water poured over its gills to keep it alive as the scan took place.