I have a small bta and a maroon clown. The minute I put the bta in the tank the maroon went to it and hosted in it. I think it made the bta a little mad due to the size of it. Right now it is pretty darn small so I think the clown bothered it just a little. I don't know about other clowns, but I can say that my maroon sure likes my bta.
Hope this helps,
Bradd