Thought Gar were freshwater. Were you over fresh water or salt?
They are, like pike & muskies, Pike and tigers have caudal fins with rounded tips while Muskies have pointed tips. I can't tell on that one. The markings look wrong for tigers and pike and there is a spotted phase for muskies.
You'll have to go back and look at the underside of the jaw: if there are six or more pores on each side, it's a musky; five or less on each side and it's a pike; five to seven and it's a tiger. Remember - it's the underside of that toothy jaw . . . wear gloves.