What's the biggest known fish in the freshwaters of your home state? We won't get into salt water or sea run species because that opens up a whole new category with boundaries that are difficult to define. Here in NJ, I regretfully have to say that the, ugly (IMO), non game, and often undesirable Carp, is probably the biggest fresh water fish in NJ. Here are the current records: Carp 65, Musky 42, and Lake Trout 32. How big are the FW fish in your state?