I just wanted some general information on red devils. We just started carrying them at the store I work at, and I have no info on them. Are they aggressive? They seem to be so far; we've lost a few due to fighting. What are they compatible with? Are they related to the Midas (They just look so similar, I think)?

They are big mean new world cichlids. They will become striking fish though.

I generally recommend rocks as a good tank mate for RDs.

I know one person who has a female RD and a female Flowerhorn and keeps them together. They're both about 8 or 9 inches and they're together in I think a 125.

I have one big boy male here currently, alone, and I have one smaller 4 inch that was in with a larger common pleco, the pleco got adopted out though.

After a certain someone's suggestion, I was considering growing out the little one to see if it was a female and try and see if I could break a tank, ahem, I mean breed them.

Most are flat out bastards some are a little more calm but very territorial. I had a few in my days the last one I had you can see as POTM. He was a bastard and needed to be kept alone he wouldnt even let me stick my hand in the tank without biting me or trying too. Hell he even charged the glass when I would put my hand to the glass. The one I currently have is a little calmer and gets along with others ok, but he is not full grown yet.

I thought they were pretty aggressive. Glad I was under the right impression. Are they worse than oscars?

Yes they are and more territorial, IMO Oscars are all show but can be aggressive.