A fish takes in the oxygen from the water using gills.

This fish can obtain up to 25% oxygen from air cutaneously if not using gills underwater.

Some groups of snails that live in freshwater respire using gills.

Most fish exchange gases using gills on either side of the pharynx.

This fish may have used gills or lungs, but the skeleton is inconclusive.

There is no evidence of spiracles, so the animals must have used lungs or gills for respiration.

They were the first fish to use gills just for respiration.

Men are able to live underwater for short periods using artificial gills.

Warm-blooded animals like whales breath air like people do because it would be hard to extract enough oxygen using gills.

Canobius is presumed to have fed on plankton which it filtered from the water using its small teeth and gills.