Has anybody kept Bichir's with Rays? What is your thought on these guys as tank mates for ray's. I have 3 rays and numerous other fish in a 500 gallon tank. Rays are just simple retic's, the biggest being 11-12 in and the smalles being about 7 in. The bichir I had offered to me is a senegal of about 5 inches. Is this just a plain bad idea?