is it a planted tank? i really think you should get 2-3 angle fish for a 29 gallon. raise them up from quarter size and they shouldn't be a problem to your danios. Once your danios start vanishing then it would be a problem. (though its gonna be a looooong time) and angles rarely catch danios anyways. ( in my experience ) w/ angels you can keep Corys and a a rubber nose pleco! good luck on choosing!