I went into one fish place yesterday, and while looking at all their coldwater fish noticed two tanks side by side that had two beautiful large telescope goldfish in each tank, when I looked closer I was shocked to see in with them where loads of sucker fish, which were constantly harrasing and sucking onto the goldfish which kept trying to shake them off well I couldn't just walk away could I so I got one of the blokes and told him they shouldn't be kept together and he moved the fancies into another tank while I was there and thanked me for telling him now if he had left them the fish wouldn't have lasted the day with the stress alone
I have an ancient Golden apple and a variety of other snails. I also have a common plec (3") which i receive mixed opinions about. My tank stays between 22-24 degrees and he seems fine. He is in with 3 comets.
My dad has a chinese sucking laoch in with two fantails. He has been in there for 3 years and leaves the other fish alone as long as he has food. We add a chunk of cucumber once a week and this keeps him away from the fantails.
I have two Chinese Algae eaters in with my two orandas and one fancy tail. The only problem is at feeding time when one of them can be aggressive (but only sometimes and especially if I put in cucumber, he thinks it is there just for him). After feeding time things go quiet again and they actually lie next to each other in the tank.