If you go with Rams, I would advise you to rehome the serpae tetras because they are notorious fin nippers, right up there with Tiger Barbs. I put a small group in with my Rams in a 20 gallon and within minutes they started picking on my big 4.5" male Bolivian Ram!
Bs is right, Rams ignore caves. If there is a "bridge" from a chunk of driftwood they may hang out under it, but mine have never used any cave I ever set up. What they do need is a lot of plants. Fake or real. That is where mine hang out, under the big leaves of my Amazon swords. They also dig their fry pits in the roots of the plants.
Ram fry are tiny, smaller than a gnat! If the parents are not good caretakers and you do not feed the fry, they will not survive. I am lucky, my male is the best parent I have ever seen. I have always suspected he is either a wild caught or close to one. He is bigger than any male I have seen and his fins are longer and more colorful too. Normal Bolivian Ram males will get up to around 3.5", but mine is closer to 5".
In my profile is pictures of my community tank that is set up to the Rams needs if you want an idea. This picture is my 20 gallon that I am growing out my juveniles. I added some real and fake plants last weekend to make them more comfortable.
