Rainbow tankmates

[Mikalicious209]

Hi all. I am completely new to the art of fish keeping. I plan on getting a rainbow as the center piece to my tank. I would like to have mucho variety tho, and I have a couple questions. First, does the compatibility change if I get an albino rainbow as opposed to a normal one? Second, will there be t too much competition for food if I get a catfish a well ? And third, if you respond, please include any suggestions for other species. Thanks for reading and any advicei might receive.
P.s. Will be in a 40g tank

 

[Mikalicious209]

By a change in compatibility I mean will it get along differently with other fish.

 

[rich311k]

What kind of rainbows, how many, what size tank?

 

[Mikalicious209]

Sorry, I forgot to specify, a rainbow shark is what I want and its gonna be in a 40usg