Fish aren't eating well

Hailfirex

Hello,

I am new to the forums and this is my first post. I have had a fish tank for years, but recently my fish have stopped eating as well as they normally do. They used to come to the top of the tank when I fed them. I know one of my problems were that I haven't cleaned it regularly. My filter is an emporer 400. I just installed the heater on it (a little late I know for the cold weather). I have set the heater for 75 degrees F. Is that correct for a 75 gallon fresh water aquarium with an irradecent barb, suckermouth catfish, Silver Dollar, Jack Dempsey? I have had some of these fish for years. I don't have a water testing kit that is up to date. Any suggestions?

Any light you could shed on this would be helpful.

Thanks in advance,

MBilyeu

I would do a 10-15% water change, then go out and get a API's master freshwater test kit to check all parameters. I would also make sure that you have nice thermometer, because if the heater dial is turned to 75 that may or may not mean 75 degrees in your tank. My heater dial is on 70 degrees and it keeps my tank constantly between 78-80.