From Official Barotrauma Wiki
Tiger Threshers are barracuda-like fish with six lateral fins, the last pair modified into tendrils. Their slender body is silvery with darker stripes and spots, including a black stripe around its neck. They are capable of doing massive damage to a submarine and its crew with a single attack. They will favor going after humans out in the water, and their razor-sharp teeth inflict heavy bleeding on their prey.