Gathering Storm - Brackish Waters

Shoot the blue tentacle!

Defeat the Monster

First a giant worm, and now a giant fish? What's next, Godzilla? There's several steps to this fight, but ultimately you're going to have to take him down from the inside. Anyway, during the first part of the battle, the monster's tentacles will grasp onto the ship and attempt to drag it down—make sure to avoid them as they latch on (standing to either extreme of the ship should do the trick), then quickly run up and chainsaw them loose.

Once you've dislodged three tentacles, stand back from the flat side of the boat, as the fish is about to chomp down! Shoot him in the left eye when it opens to knock him loose. Do this once more to cause his mouth to open—quickly run inside! Now you'll spot six tentacles ahead, and you're going to have to shoot three to get to the next step. However, only one tentacle is vulnerable at a time: the blue one that's wiggling around. After shooting it, another tentacle will become active—shoot it too. After shooting three tentacles, the weird thing in the back of the fish's throat will begin convulsing—toss a grenade inside it to finally deal this fish some damage!

Repeat this process two more times to do him in for good. Oh, and if you run low on grenades, more can be found scattered around the boat.