I was born in Wichita-- Kansas heat can be miserable!
I am sure there are more knowing people on this board that can help, but a few additional things you might consider would be to make sure you are not using any hood lighting (they can generate a lot of additional heat) and even table lamps within a few feet of the tank can create a tremendous amount of heat. Too, though generally not a problem with cooler tanks, any aquarium equipment (e.g. warm air pumps. etc.) that are close to the walls of the tank can boost higher temperatures even higher. Heat generating equipment housed under tanks can also add a lot of warmth via the bottom of the tank as the heat rises- especially if contained in closed cabinets under the tank.
I believe higher water temps also reduce available oxygen levels. I would make sure there is a lot of areation (air stones and/or dropping water level a bit to allow teturning water to break surface tension); this may reduce the apparent breathing stress.
If forum members state my information is wrong, please ignore my advice; I have been away from fishkeeping for a while so my info may be out-of-date.
Good luck.