1980s story with strange deadly creatures send to a different planet

I am trying to find a book I've read a while ago, 80s to be more exact hence my assumption that it was published somewhere between 70s and 80s.

I remember that there were some strange deadly creatures that once caught were sent to a different planet. The name of that planet eludes me but I do remember that it had number 3 in it.

I also remember that the book cover had a picture which included flying manta rays and behind them there was some sort of a space ship or space colony.

EDIT: The book was not part of a trilogy.

I just remembered that there was a search for some chemical. Antitoxin maybe?

Thanks for the help.