Can they be kept with Cichlids happily?
Are they as agressive as their counterpart the Red tail?
He hasnt chased any of my silvers yet, could he be a calm shark?

I had a Rainbow Shark for several years, and he was very docile. no aggression ever!

I love them and they have the same Ph as my GT's of around 7.5. Would another rainbow in the tank trigger agression?

iv kept red tails for a while, currnetly on my first rainbow shark....in comparison there is very very little agression, very differant fish

sorry nvr kept them with cichlids tho

i have in the past kept a rainbow in my oscar tank until he died of old age.(he was about 6 years old) i found they are very similar to their cousin the red tailed shark and have the same temperment and needs. also they are very aggressive within their own species(something i learned the hard way when i introduced an albino rainbow into my tank).
all in all i found mine to be a good tankmate for my oscars and as long as your oscar doesnt try to eat him they should get along fine.