fish for beginner

[Falconeer999]

I have a 10 gallon tank I've been running for 3 years. Currently I have 1 angel fish (he grew fast and really needs a 20+ gallon tank), 2 tiger barbs, 3 tetras, 3 GloFish (is a zebra fish with jellyfish DNA to make them different bright colors), and an algae eater. Tank is stocked with 3 or 4 different varieties of live plants. I have an Aquaclear filter that's good for up to a 20 gallon tank. I used to have a heater in the tank but I took it out about 8 months ago when I was having some sudden algae problems. Water temperature stays pretty constant between 73-75 degrees and all the fish are doing fine so I've kept it out.

At one point, I had 2 female bettas in there - they did NOT get along at all. One was already bigger than the other when I tried to introduce them. The larger one would chase the smaller one all around the tank and nip at her fins (but she wouldn't chase any of the other smaller fish - weird). I put a mesh divider in the tank and let them get used to each other. They would flare constantly for the first 2 weeks or so, then it petered off. After around 3 or 4 months I took the divider out and they were perfectly fine and would sometimes "school" like the other species would, though not too often.

Edit: I've had a horrible time with dwarf African frogs. They never last more than 2 or 3 months. I've had them in the 10 gallon tank and in a separate 2.5 gallon tank. I just have no luck with them.