We have lost over 40 fish in the last couple of weeks. All cichlids! They stopped eating, then developed small cottonball like specks on their entire body. From there red bruise like blotches appeared, starting by the fins and spreading over the body. They clamped their fins and lost their ability to stay upright. Soon after this, they died. Can't find anything on the internet to help us stop this. Looking for advice. We have a catfish and a pleco in the same tank. They have not been affected but we are wondering if they could carry the problem if we put them in a different tank. Any help is greatly appreciated
40 fish!? This does sound like an infection... specifically, this sounds a lot like White Spot (aka Ich). Check out our existing question What, exactly, is "ich"? or this link with more info and treatment. The 'bruises' may be a secondary infection even.
As with most fish illnesses- quarantine is the best first step to troubleshooting. I would start a fresh tank for the new Cichlids, but if you can't, follow some of the treatment steps in the link above, but take it slow: environmental changes are always stressful on fish. Be mindful of oxygen changes and temperature (!and pH!) changes.
In my experience cat fish are hardy little beasties, so it might be that their skin type and where they live in the tank plays a role in them not getting sick. They, and your plants may well be contributing factors. I know some plants may be 'carriers' if they've lived in infected tanks before.