I have a 7.5 gallon Mr. Aqua cube with a filter and a heater kept at 78F with low light plants. I only have one betta currently in it. He is tail biting for unknown reasons (I'm guessing maybe stress or boredom). I was wondering if I can add more fish to maybe give him a party? I've been adviced that rasborias and danios will work well but they must be kept in schools. I do not want to overstock. Does anyone have any recommendations? I might just add some ghosties and a nerite maybe.
Also, what are your recommendations for a 10 gallon tank under the same conditions?