barefootKATE, is this your first aquarium? If so welcome to the hobby. It can be very addictive. There are sooo many different kinds of fish out there. A common type of fish out there is the African Cichlid species. They can be found at most any main stream pet store (petsmart, petco, etc.). And these fish fish have some pretty serious personality. They will watch you as you watch them. They will follow you as you walk past th tank. Just fun fish in general. It is kind of strange thinking that fish are fun, but head down to a
LFS and look at some Yellow Labs. If you touch the tank and move your finger around, they will follow your finger.
These fish do not like plants. Or rather they like the plants too much and wii eat on them to the point of having no more plants at all. And if they for some reason do not feel like eating them, the will dig them up and you will come home to a plant or 2 floating on the surface. So stick with the rocks and driftwood if you go this way.
They can be a little more aggressive. But I have found that if you keep them in pairs (1 male, 1 female) they tend to be much more manageable.
If you do decide on this species of fish, just make sure to look for the maximum size of the fish before purchasing them. I know that Petsmart has the size posted on the tag. But a
LFS will be able to tell you the size too.
DeFeKt, that has got to be the best method I have ever seen to tell if a tank is overstocked!