"There is always something waiting at the end of the road ... if you're not willing to see what it is ... you probably shouldn't be out there in the first place."
If you're scientifically minded (and you really want to know), you could try a dichotomous key at your local library, such as "Fishes of the Gulf of Mexico, Texas, Louisiana and adjacent waters" by Hoese and Moore. I'm sure there are other books for different regions.
Although you are asking the wrong question in the wrong place, lol. Good shot.