Fish Seem Depressed

Question
Hi.  I have two sarassa comets in my 100 gallon pond.  I know they will slow their eating and prepare to hibernate in the fall but they already seem kind of "blah".  Isn't it too early for them to cut down on their eating? (I'm in Virginia Beach, by the way).  They used to swim fast and dart around now they just kind of lollygag.  I have a pump and water movement so I don't think lack of oxygen is the problem.  My plants (especially the water hyacinths) seem to be in overdrive.  Could it be that there are too many plants and not enough room for them to swim? Any advice would be welcome.
Thanks!

Answer
Hi Jessica,
Thanx for your question.  It has been very hot this year.  At least it has here in Kansas Since early July and just now starting to cool down.  The heat will also cause fish to reduce activity.  I doubt if you have too many plants.  I think it has just been very warm.  I hope this helps.
Tom