I would not put more than one fish in a tank this small. It is very difficult to maintain good water quality in a tank like this and having two fish would increase the problem. I also agree that they can be aggressive and a tank this small will most likely result in one killing the other or at least stressing it constantly. Realistically you should get a tank that is a little bigger, maybe 20 gallon, if possible. It will definitely make it easier for you. In a 20 gallon you would be much better off if you choose to get both fish.
With that said I think either one would do just fine in a tank like that. All you would need is a little sand, couple rocks or decorations, and some powerheads and/or sponge filter.