I was just fooling around w/ the overflows when i started looking at my albino birchirs i went to look at the other one and realized the wasn't there! I took count again and I'm missing a Salvini. So i'm missing a 6"bichir and a 3-4" salvini and the only way out would have been the overflow. I never thought they would go down it. I guess i'll have to take them apart tomorrow and try and get the fish out. So this is probally what is decreasing the flow.