This Gigantic Goliath Grouper Tries to Swallow a Diver’s Whole Head in a Single Gulp

Swimming in the ocean is an incredible experience, with astonishing surprises for even the most seasoned divers. Take the goliath grouper, for example — these enormous fish are both awe-inspiring and a bit nerve-racking due to their imposing size and austere presence. While they typically leave humans alone, the diver in this YouTube video quickly discovered that it’s best to keep your distance from these underwater behemoths!

Just How Big Do Goliath Groupers Get?

Goliath groupers (Epinephelus itajara) are true ocean giants, living for over 30 years and growing to impressive sizes — up to 8 feet long and weighing as much as 800 pounds! Unsurprisingly, these colossal sea creatures have gained a lot of attention over the years, and they were once highly sought after by fishermen. Unfortunately, this led to overfishing in their habitats, causing the fish to become critically endangered. Fishing for goliath groupers became illegal in the United States and in the Caribbean in the 1990s, although Florida recently began allowing a very limited harvest. As of 2025, goliath groupers are listed as vulnerable by the IUCN, but because they grow so slowly, and despite some localized recovery, the species remains vulnerable and has not fully recovered.

Goliath groupers live in the warm waters of the Atlantic Ocean, especially around coral reefs and artificial structures. They can be found off the coasts of the Florida Keys, the Caribbean islands, the Bahamas, Brazil, and parts of Africa. They usually stay in shallower waters, no deeper than 150 feet.

Their bodies are yellow-brown, gray, or olive, with mottled bands and spots that help them blend in with their rocky environment. Adult goliath groupers don’t have many natural predators besides large sharks. However, young, smaller groupers rely on this camouflage to hide from moray eels, barracuda, king mackerel, and sharks.

Are Goliath Groupers Dangerous to Humans?

Goliath groupers have sharp teeth that help them grab their prey, which they swallow whole. They eat octopus, crustaceans, stingrays, other fish, and young sea turtles. They tend to live alone and can be quite protective of their territory, readily defending it if they feel threatened. But does this behavior apply to humans as well? Why did the goliath grouper in this YouTube video try to bite the diver’s head?

Generally, goliath groupers are peaceful and not aggressive toward humans — we are definitely not on their menu. However, divers should remain cautious around these fish, especially the larger ones, simply because of their massive size. Anything that large could pose a threat, even if unintentionally.

Groupers will usually give a warning before attacking. Many divers report that the fish will make a loud grunt or barking sound if you get too close. While it’s rare, there have been instances where a goliath grouper charged or bit a human who got too close. Fortunately, the diver in the video was not injured by the fish’s sudden change in behavior. However, it serves as a good reminder that the ocean and its inhabitants can be very unpredictable.