Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Cool water fish like Dojo Loaches, Goldfish, many Barbs, Cories and so on cannot handle the heat as well as warm water fish like Angels, Discus, and Clown Loaches.
Part of the problem is lack of oxygen. Warm water holds less oxygen. Aerating the water as you have done is one very good way to help the fish.
Using bottles of ice can help. May not lower the temperature by much, but you do not want a drastic reduction. Sometimes just a couple of degrees is enough to make the difference.
Removing the lid and aiming a fan across the top of the water can help a lot. If you have fish that jump arrange a screen (like window screen or coarser) across the top. It will interfere with the fan, some, but it is better than losing jumpers. There will still be some evaporation from the tank. Top off with cool, RO water.
I cope by trying to keep the house as cool as possible- closing curtains for example.
Turn off things like the lights in the tanks, but keep pumps running for optimum water circulation.