A sunfish is a small, colorful freshwater fish that lives in ponds, lakes, and slow-moving streams across North America. These fish get their name because they often swim near the surface in sunny, shallow water, looking almost like they're basking in the sunlight.

Most sunfish species are only about the size of your hand, with round, flat bodies and beautiful colors: blues, oranges, yellows, and greens that shimmer in the water. The bluegill and the pumpkinseed are two common types of sunfish that many kids catch while fishing. Sunfish are popular with young anglers because they're plentiful, they bite readily on simple bait like worms, and they put up a fun fight on the line despite their small size.

Male sunfish build circular nests on the bottom of ponds and lakes, clearing away debris to create clean spots where females can lay their eggs. The males then guard these nests fiercely, chasing away any fish that swim too close.

The word sunfish can also refer to the ocean sunfish, or Mola mola, one of the strangest fish in the sea. These bizarre creatures can weigh over 5,000 pounds and look like someone designed half a fish and then forgot to add the back part. Despite the shared name, ocean sunfish aren't related to freshwater sunfish at all.