DeadFish

From Spent Lemon:

A chemical tanker for a large American corporation, after an unfortunate accident with a sword fish, has spilled millions of gallons of toxic chemicals into the ocean. Thankfully, the chemicals separate after a few hours in water, but before they could disperse, an entire school of fish passing by was exposed! This has given them certain unusual mutations . . .

You have been assigned a mission by the U.S. government: destroy these mutated fish before they can reach the sea floor and contaminate the plants. Since the government seems to think that duct tape is a powerful defense against chemical and biological weapons, your sub has been equipped to shoot rolls of the grey ribbon.

Good luck, fish killer!