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Today on Animal Fact Files we’re discussing groupers. These fish are classified in the same subfamily as sea bass. There isn't a definitive distinction between these two fish. In some species the names are used interchangeably. The common name "sea bass" may also apply to fish species outside of this subfamily, so we'll be sticking with the common name "grouper" to describe them today. There are approximately 170 living grouper species as of this recording, however, this number will likely change with new information as genetic sequencing reveals relationships among these species.

Groupers live worldwide in warm marine and brackish water systems. Young groupers are more frequently found in brackish water estuaries as well as inshore seagrass beds and coral reefs with places for them to hide. Adult groupers can be found on continental slopes where the seafloor drops off. They've been observed over 900 feet (274m) deep depending on the species. Adults may also live in reefs specifically with large crevices. Sunken ships are frequented by these large fish. Groupers are well known for their Goliath sizes, but not all groupers are giants. The largest groupers reach more than 7 feet (2.1m) in length and over 600 pounds (272kg) in weight, but smaller species may not even reach a foot (30.5cm) at full size.

Groupers are typically brown or grey in color, but some have patterns and deep water species may appear red. Some species can even change color. Like an octopus, groupers can blend in with their environment by changing their appearance. They also change their sex! Many groupers are protogynous hermaphrodites. This means that they begin life as a female and transition to male once they reach a certain size. Males are often the largest groupers around. Some species may have both male and female reproductive organs, as well.

Outside of the breeding season, groupers are solitary, but when they gather to mate they form groups that can number in the hundreds to thousands depending on the species! Groupers migrate to breeding grounds and are promiscuous meaning they'll have multiple partners. A female grouper may lay millions of eggs. The eggs and the larvae that hatch from them are planktonic. It takes anywhere from a few days to a few months for these to develop. Some species, like the Goliath grouper, take years to reach reproductive maturity, and these fish live at least one decade in the wild, with some species estimated to reach 50 years old if left undisturbed.

The amount of time it takes for groupers to reach maturity can be a detriment to their survivability. These fish are overfished in many parts of the world and their populations are unable to keep up. Many are listed as threatened with extinction and some are protected from fishing. Natural predators to groupers include lemon sharks, tiger sharks, reef sharks, moray eels, snappers, and even each other from time to time. Groupers themselves consume coral reef fish, crustaceans, and molluscs. They use suction by opening their large mouths to draw prey in and swallow them whole. They're some of the only predators to the lionfish which are invasive in parts of the world.

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