I guess some of it depends on what you enjoy watching.

Tetras are community fish, and they do well if there are 5 or more.

I have kept one male betta in a community tank with tetras. The first 4 bettas I had were fine. The fifth one got returned next day; he was attacking EVERYONE!!! I haven't had much lick with bettas, as you can tell, they live about 8 months in my tank.

My tank is 19 litres. I love seeing lots of fish, so I stick with the little ones. LOTS of them! I have 16 tetras, 3 different types. They swim together and then in separate schools. I really enjoy that.

I had great success with plecos when I lived in my apartment; my tank ALWAY'S had algae, ha ha. Here in my house, plecos don't eat unless I feed them, so I don't have any. I also had great success with angels in my apartment; but here they don't last long.

I bought a house less than a mile from my apartment, same city so the water is the same. It has to be the difference in the light and maybe in the heat.

I like the pristella tetras. I have NO luck with neon tetras, they seldom last 2 weeks for me. Go figure, supposedly the easiest fish to keep, ha ha.