A 75 isn't really that large considering the cichlids you're interested in. As adults, I wouldn't do more than a pair of severums in a 75. A 125 would be better. I would completely avoid oscars for now. They are fast growers and do put off a lot of waste, so you'd need to be doing large water changes on a frequent basis and they'd still probably get too large before you upgraded the tank. I would wait until you actually have the new, larger tank ready before buying oscars.
Red devils get that name for a reason. I wouldn't mix them with severums... or any fish, really. If you already have four severums, that's going to be too much for a 75 once they hit adult size. I would just leave the tank as-is and get some colorful dithers like large tetras or rainbowfish to mix with them. Also, severums usually do fine with angels as long as you're not working with fancy veil varieties -- the long fins don't mix well with tankmates because they often get nipped at, and the veil angels don't swim around as agilely as standard angels do. I would say on an aggression level that angels can be just as pugnacious and feisty as severums, especially when spawning or when confronted with other angels.
I would not recommend Uaru at all. You're talking about another large cichlid that gets in the 10"+ range, and is also an eating machine that will produce a ton of waste. Like oscars, they need regular large water changes to keep them healthy and avoid things like HITH. They can be sensitive to nitrates. And if you're looking for something colorful, that's probably not your best option anyway.
Red devils get that name for a reason. I wouldn't mix them with severums... or any fish, really. If you already have four severums, that's going to be too much for a 75 once they hit adult size. I would just leave the tank as-is and get some colorful dithers like large tetras or rainbowfish to mix with them. Also, severums usually do fine with angels as long as you're not working with fancy veil varieties -- the long fins don't mix well with tankmates because they often get nipped at, and the veil angels don't swim around as agilely as standard angels do. I would say on an aggression level that angels can be just as pugnacious and feisty as severums, especially when spawning or when confronted with other angels.
I would not recommend Uaru at all. You're talking about another large cichlid that gets in the 10"+ range, and is also an eating machine that will produce a ton of waste. Like oscars, they need regular large water changes to keep them healthy and avoid things like HITH. They can be sensitive to nitrates. And if you're looking for something colorful, that's probably not your best option anyway.
Now I figure if I'm gonna get another tank, its gonna be bigger, much bigger. Was considering doing a plywood build but I want to own my home before I do that.
