I have three Blue Zebra Danios in my Community Tank, which at the moment has 20 fish. I have a 3/4 inch Clown Loach, a 2.5 inch Bengal Loach (or whatever they want to be called), three 1 Inch Dalmation Molly's, a 1 Inch Pl*co, 5 half inch Neons, 3 Beunos Aries Tetra's ranging from 1 inch to a monster 3 incher, 3 Head and Tail Light Tetra's, and my Blue Zebra Danio's.
In my tank I find that my Danio's literally have prizfights with each other and ignore EVERYTHING else. The Molly's and the Zebra's should as far as I know be the most aggressive fish I have, but my little Clown Loach tends to be the most aggressive fish I have.
I dont know if I am reapeating anyone here, and I am not an expert but this is from my experiance, I have had my Zebra's for about 3 months and had no problems with them. I think it may be your tank size?
Please correct me on any errors.
TY