"Life flashed past before my eyes," writes Christian Pulisic in the published clip on his Instagram.
The former Borussia Dortmund player tricked with a ball on a boat edge when he lost his balance and fell on a Goliath grouper.
The United States has classified the fish as critically endangered - and it has been protected in the country since 1990. The fish was kept in a line and the American was helped out of the water, while the line remained attached to the animal.
Gets criticism
The clip has been spread on the social platform Twitter and has caused organizations and individuals to react.
"Injury to an acutely threatened Goliath group for a social media video is a new bottom line," the animal rights organization Blue Planet Society wrote via its Twitter account.
"That fish, a Goliath grouper, is completely protected.
We hope they released it, ”writes the US National Oceanic and Atmospheric Administration (NOAA) on the same platform.
"This is not fun or funny," a user wrote on Twitter.
In the state of Florida, in which this happened, the Fish and Nature Conservation Unit has guidelines stating that this species of fish must not be damaged and must be released back into the water.