A bluegill is a freshwater fish often referred to as a brim, and is a part of the family of sunfish native to North America. A sunfish, actually called the ocean sunfish, is a saltwater fish, related to the bluegill as it is also in the sunfish family.
Bluegills tend to grow up to 12 inches long and weigh 4 lbs. while the ocean sunfish grows up to 10 feet and 2,000 lbs. and is the largest bony fish known to man. This gives the bluegill a distinct speed and ability to dart much faster than the ocean sunfish. The sunfish is native to tropical waters, where as the bluegill makes its home in ponds, lakes and rivers. The ocean sunfish survives on a diet of jellyfish while the bluegill eats anything, plant or animal, that will fit in its mouth.
Bluegills have very distinctive coloring, with deep blue and purple on the face and gill flap, dark green-colored bands down the side, and a sunny orange to yellow belly. The ocean sunfish ranges from being brown in color to silvery grey and white, being much less vibrant than their freshwater relative. The ocean sunfish possesses camouflage abilities to help it hide from potential predators.