Need help deciding on fish

[The Dinkster]

Hello friends, I recently moved into a new house after living in the dorms my first year of college. Unfortunately, I was not allowed pet fish in my room, so I couldn't bring mine down. Now that I have my own house where I'm allowed fish, I have a 30G starter tank set up and I have an idea of what I'd like to put in it, but I'm not sure of what to choose. I know I would like a bichir, type is to be decided, or a couple rope fish. I think both are awesome and look great, but I'm torn between the two. My main question is bichirs beef up very nicely as they grow, and get very thick, but I don't know if the same can be said for rope fish, do they stay relatively skinny, or do they beef up as well? Any help is greatly appreciated, and feel free to add comments about which one you think I should go with!