Bettas

I have never had bettas before, and I want to try them out. Atm they are in my 30 gallon with some tetra fish and danios, I know they  can be fin nippers so I need to watch them, so for that I  have a seperate tank around 15 gallons just incase. Day two and it seems like its all good :3  let me know if you have had bettas and have some tips or info for me that I dont know about. 

sorry for the bad quality xD also tried to paint out a super annoying flash glare on kay the picture haha hopefully its not to obvious