Lately my girlfriend and myself have been going to different creeks and catching various specied to put in my 50 gallon tank. Right now it has 4 large crawdads, 10 minnows (shiners I think), a few different snails, and one lone catfish that's about the size of the minnows. I've got a couple of plants that we found in creeks placed in there too. Everything seems to be doing very well right now, I just want to make sure is stays that way. The crawdads seem to be eating the snails which is fine with me cause i hear snails are hard to get rid of. Has anybody done this in here that might give me some advice on upkeep of such a system?