Fish Thicc is the worst of the Fortnite Chapter 4 Season 4 Battle Pass skins. Epic Games basically just made Fishstick muscular and stuck him in a tank top. Nothing about the skin fits in with the heist season; in fact, it just looks kind of weird next to all the innovative designs we previously mentioned.
Fishstick has always been more of a meme character in Fortnite, so maybe the skin works in that way here as well. But you will certainly not be seeing many Fish Thicc skins on the map when there are so many better options.
Players can unlock Fish Thicc on page 5 of the Battle Pass for nine Battle Stars.