Yes, there are fans on both heatsinks. They are just not super powerful, just like a normal CPU fan... So I am considering cutting the top, putting the coldsink in the tank and the just outside of tank level. I think that would do the maximum cooling, I just am a bit hesitant to cut the top, since of course eventually (several years from now) I will indeed sell it... That certainly isn't great for resale, but what ever is best for the plants... THANKS AGAIN!!