How do you give a fish a CAT scan?

That sounds like the setup for a joke. But zookeepers in Denver, Colorado asked that question seriously.

The Denver Zoo’s aquarium features all sorts of tropical fish. Earlier this year, a zoo worker noticed something concerning. One of the French angelfish was swimming with a tilt. It had trouble floating.

Animal care specialists took the fish to the Helen and Arthur E. Johnson Animal Hospital. There, veterinarians gave it a CT scan.

CT scan (or “CAT scan”) stands for “computerized tomography scan.” Tomography is a way of taking 3-D images of something’s insides. Normal X-ray machines shoot X-rays in a straight line. They take flat images. But CT scanning uses a large, circle-shaped machine. The X-ray beam spins around. The machine sends the images to a computer. The computer sorts them into a detailed 3-D picture.

But the animal hospital’s CT scan machine wasn’t built for fish. It’s big enough to scan a 700-pound grizzly bear! The veterinarians had to get creative. They sedated the sick angelfish. They balanced it on a sponge in a plastic container. During the scan, they poured water over its gills. This kept the fish alive.

Doctors quickly discovered the fish’s affliction. It had enteritis. That means its intestines were swollen. This gave the fish gas—so much gas it couldn’t swim right!

Thankfully, the solution was simple.

“[The fish] was treated with antibiotics,” says zoo spokesperson Jake Kubie. “It’s doing much better and swimming normally.”

This might sound like a lot of work to help one angelfish. But caring for little creatures can still be worthwhile.

God cares about tiny sparrows. (Matthew 10:29) He cares for each one of His people even more! Jesus told the parable of a shepherd who left his whole flock to find one lost sheep. That one lost sheep represents you.

“What man of you, having a hundred sheep, if he has lost one of them, does not leave the ninety-nine in the open country, and go after the one that is lost, until he finds it?” — Luke 15:4