I thought that I would share this quick easy idea. Last year we decided that we needed a fish. A Beta fish is what we got because they are pretty easy to take care of especially if you give it this setup. I used a vase, small peace lily plant, distilled water (room temp), rocks and a plastic lid. I washed the rock and vase first, and cleaned all of the dirt out of the roots of the plant as well as trim the roots so the guy had some room too swim.
Then using my plastic lid I first cut a circle that was the same size as the mouth of the vase. I cut a smaller hole in the middle that was a little bit smaller than the plant so that the plant would stay put.
I put some big rocks in the bottom of the vase for decoration and added water to almost the top. I then put the fish in and put the plastic ring with the plant in it on top and added small rocks on the top to hide the plastic and secure it in place.
The best part is when you have the beta fish in a vase with a plant you don't need to feed it, they will eat the roots of the plant. It doesn't hurt the plant either. I had one for years growing up with this setup, if you still want to feed it, it's only a couple dollars and it will last you forever. I replace the water when it starts to turn murky, and how often that is depends on how much sun it gets. The more sun the murkier the water gets and faster. I put it in a place where the sun doesn't hit it very directly and I haven't had to change the water in 6 months. This was tons of fun to put together with my daughter as well, she named the fish "Reddy"