Heather Bair-Brake is with the the CDC has received several reports of salmonella infection from reptile terrariums. Australia has recently reported several cases of salmonella that have been serious enough to send children to the hospital. Twelve million Americans have aquariums.

"We’re telling people that they should just take precautions when they’re taking care of their fish and washing their tanks," Bair-Brake said.

What kind of precautions should you take? The CDC says it’s best to wash fish tanks, bowls and accessories outside. If that’s not possible, "make sure that you clean the sinks and counter tops with a mild bleach solution to get rid of any germs," said Bair-Brake.

Another safety tip: after you’re done scrubbing the tank and everything else, scrub your hands.

For children under age five who tend to put their fingers in their mouths, you need to be extra careful because their immune systems are not fully developed. "It’s very important that parents watch their children and make sure they don’t play around in the tank," says Bair-Brake.