I had a betta for about a year, just in a bowl, and when I got a tank I decided to add him to the tank so maybe he would have more room. However, he didn't cause any problems.. My 2 male rainbow fish overtook him and he died about 2 months later. So I have noticed that the 2 males are quite aggressive to eachother as well.. Just wanted to tell everyone! My friend also has a tank where the rainbow fish are taking the guppies over as well. So any brightly colored male gets put on the hit list I suppose
