I love all animals, and when I was in college, my tiny apartment would only allow fish. So, I took what I could get, and I've had a fish tank ever since.
Originally, I got fish for some company, but I realized that having them around is really relaxing. I love to hear the gentle bubbling of the filter and watch the graceful movements of the fish's shimmering fins. It has a wonderful calming effect on my mood.
Want to know how you can set-up your own peaceful community tank? Then
Having a fish tank is really fun because it's really not a lot of work - you feed them once a day, change the water twice a month (more often if you have live plants, less if you have goldfish), and clean out the filter twice a month (alternate doing this with the water changes).
You can go to a pet store and they'll have all you'll need, and be able to answer all your questions. Just so you know, you need to set up the tank with water and the filter running without fish for a few days.
You can also go to town picking out different plants, colored gravel, and interesting tank decor. I'm partial to mermaids myself.
Then, you can add a few small, inexpensive fish, and let your tank cycle for 4-8 weeks (it takes this long to establish the right kind of bacteria in the filter that removes the toxins that your fish poop out).
After the 4-8 weeks, if the original fish you put in there are doing well, go ahead and pick out some more fish. Keep in mind that the fish you buy may grow, so don't get too many fish - an overcrowded tank will stress both you and your fish.