Currently I have 3 inside my 55 gallon and after the most recent addition it inspired me to collect more info and research them alot more as I am now quite fond of all of them and want to make sure they prosper very well in my tank. The cats I am keeping now are: 1 common pleco, 1 synodontis lace cat, and the new addition is a striped raphael cat, which for some reason is considerably larger than the other two cats. (please forgive the use of common names as I am new here and will soon be frequent with the scientific names)
After observing these fish for several months I have developed several opinions and have generated some questions to help me along in caring for them.
I have no idea of the origins of any of these cats, I think one is for sure from south america after searching this site for a few minutes so if anyone can chime in on that issue I can direct further questions into the right category. Id like to know if these three will mix well together, if they will crossbreed(which isnt what I am aiming for). When I just had the common and the lace cat they shared one common hiding spot and I could barely view them ever, but i did notice that they would "play," with each other or get into scuffles with each other while maintaining that certain spot. When I dropped the striped raphael in I reaaranged some scenery including the hiding spot and the two have since separated the striped raphael now holds that spot to himself, while the common pleco is now out and about most of the day attaching himself to the glass. This has made me fairly happy along with bringing me some serious concerns. Since he started moving all about he is more prone to abuse at the hands of my tank baddie M. Chipokae. I have obsevered several beatings

As far as some other questions..... I will have two 55 gallons with approx. 15 cichlids each, I believe these two tanks can hold up to 20 fish without overloading the bioload if I have enough filtration. So for the other 5 I would like to place catfish. Is doing this okay?? Should I be species specific( all striped raphael in one tank, all lace cats in another, etc.) Will doing this promote more activity during daytime hours since the numbers are increased?? Will they feel more comfortable??
Do cats school in any way?? How exactly do these cats mate and reproduce????
These are just a few questions I have and hope noone is upset that I wrote such a looong post, I will do some more research here, and take your advice as given, thanks to everyone for reading and/or responding and to the administrators/moderators I just want to say this is defintely one awesome site, thanks for all the hard work!!!!