Banded leporinus should be fine in a 75gal, but a 55gal would probably be too small to house one in permanently in my honest opinion depending on the tanks dimensions;
http
/badmanstropicalfish.com/profiles/profile1.html
Chinese algae eaters are tempermental fish and can become particularly agressive/territorial as they mature. Bottom dwelling fish, slow swimming and flat bodied fish are at risk from attack from CAE's- not all chinese algae eaters become agressive as they mature, but the majority do in my experience. They do not make the best community fish (primarily because they can be very unpredictable in how agressive they turn out to be when they mature- one day the CAE could be fine with its tankmates, the next day it is chasing them around trying to kill them etc), but can be kept in community tanks if a lot of care is put into their stocking.
With CAE's i would personally only advise small and fast swimming fish like danio's with them, or large shoals of small and indentical fish like neon tetras as CAE's are least likely to go for these sorts of fish- most other sorts of fish are risky or very risky to keep with Chinese algae eaters.
This would be a problem though with the sun catfish, personally i wouldn't stock any small fish with it because it is a predatory fish.
So personally, i would decide between having the CAE or the Sun Catfish as otherwise you will not have many safe fish stocking options open to you if you keep both fish in the same tank together. A CAE only needs a 30gal long tank though if you decide to keep it, this is what i would recommend keeping it in rather than having it in the new main community tank.
I have no experience with keeping sun catfish, however i trust practical fishkeeping articles on fish and this is what they have to say about them;
"There's an error in the Baesch Atlas regarding the size of this fish, which incorrectly claims a maximum size of about 13cm/5". This has lead people (including dealers) to believe this is a small species. It isn't. Museum records show that H. brachysoma can in fact hit 45cm/18", although 30cm/12" is more common in the aquarium."
"Although some shops are mistakenly selling this as a community fish, it really isn't to be trusted alongside small fishes. Small ones aren't much of a problem alongside equal sized fishes, but the species is capable of eating anything it can fit in its mouth. It can be relatively shy during day, so provide plenty of shelter in the tank to allow it to hide. It mixes well with other large peaceful fishes, such as big barbs and cichlids. It can also usually be kept in groups without too many problems, indeed it may be a shoaling fish when young. However, the larger ones I've kept became less willing to share their tank with others the bigger they grew. For three or four juveniles or subadults, you'll need a tank of at least 120x45x45cm/48"x18"x18", ideally a bit bigger. Unfortunately, the colours don't stay quite as bright as the fish get bigger."
For more info see;
http/www.practicalfishkeeping.co.uk/pfk/...?article_id=295
What is the exact dimensions of the new tank (length, width, height)?
), so I thought I'd rescue them. I can't really take one and not the other. I figure anything bigger than what they are in now will be better.
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