Lets not highjack the thread here... I just set up a 5.5 gallon tank with shellies (don't remember which ones have to ask BoyFriend) and they are so comical! They are so small to begin with that the tank looks kind of empty, but i am resisting the urge to put any top dwellers in there, once they get a bit bigger (they are like .5 an inch) it will start looking fuller. We have them on a calcium sand black sand substrate and it looks really cool. The only time that we use chemicals (I don't like using them either) is when we buffer up the new water that is added in order to keep the pH constant. Also don't forget about adding Cichlid salt! IMHO it really helps bring out the best in Africans. Best of Luck!