Should i add a discus?
Personally I wouldn’t, but that is only because of my own philosophy on aquariums. I like tanks that are representative of a natural ecosystem. Having the Danios and Gouramis prevents that. But as I said that is my personal bias. Other than that I see no problem with what you want to do. Discus are from very soft acidic water in the wild, but many breeders today raise them in hard water with no problems. The domestic strains have just had that intolerance breed out of them to a large degree. An Angel fish is not going to kill your Discus, unless it is really small and the Angel is really large. Angels just aren’t that aggressive, and Discus max out at around 9 inches which is much larger than Angels. There is a risk with a Pleco, but not all of them do it, and if you catch it happening you can change out the Pleco for another. The only time I keep a single species tank is if I am breeding a sensative species such a Discus or Angels, and then it is a single pair tank.
