Nope! That's one of the best things about snakehead. Not only have they inhabited shallow, low oxygen water where there really weren't any game opportunities in the past, but they also bite aggressively all summer long. I will say that they are harder to catch as the summer wears on. By August, the spatterdock and hydrilla beds are VERY thick and harder to find open holes/channels where you can pull a fly through, but you can still catch them. A falling tide will force them closer to the edges of the hydrilla and makes it slightly easier.