My experience of CAEs is that the only thing accurately described about them is their county of origin: China.
When theyre young theyre nice peaceful little critter that eat algae. When they grow, which they do quickly, they become highly aggressive, and capable to taking on much larger fish than themselves! Some people have reported that they can keep a single fully grown CAE in a community tank with no problems, but this has never been the case for me.
So much so that there is a tank under my desk that is dedicated to a single CAE that I dont want to re-house because it so aggressive and dont want to kill because... well, its not ill or anything, so it would be just wrong to do so.
CAEs will eat the slime coating off of flat bodied fish. My CAE attacked my Harlequin Rasboras resulting in the death of three in one day. They had been in the tank with no troubles until that day for months and months.
CAEs are, typically, not a sensible buy when it comes to a cleanup fish. Siamese Algae Eaters are much more appropriate to community tanks because they are not aggressive and also eat algae.