I love Bettas.  They're an amazing fish that is beautiful to look at and doesn't take a lot of time and effort to take care of.  Bettas also known as Siamese Fighting Fish.  The fish earned that nickname because the males of the species usually don't get along with one another and they will fight to the death if kept in the same aquarium.  A hardy fish that will live in a small tank (I used to bring mine to work).  All you need to do is change the water every other month (make sure it's free of chlorine and fluoride) and place it in the warm spot in your dwelling.  I have a small tank that can be split in half and sometimes I put two males in there.  They will puff up and show off in front of one another like peacocks.

Bettas are a curious fish and get animated when they see you because they know it's feeding time.  Sometimes if they want your attention they will swim around in circles.  They're not that expensive, but the more colorful ones cost a bit more.  I usually buy mine at Petco or a local pet store.  You can feed your Bettas frozen brine shrimp, plankton, flakes or pellets.  I feed mine pellets because the nosy fish will eat those.  I had problems with the flakes.  Not only will they not eat them but the flakes dirty the tank water.
If you want a fun hassle free fish then you'll want to get a Betta.  A perfect pet for those who don't have a lot of space, live in an apartment or for those with busy lives.