Hiya folks! I've been lurking for a while, but decided to jump in and participate. I've got a black ghost knife that I acquired recently. I wasn't planning on getting one, but this one needed a home quickly. It's currently in my 65 Gallon w/ a few cichlids, including jaguars, and oscar, a red devil, and a pair of jewels. I also have a trio of bumble bee cichlids in there that will be gone soon. The BGK is approx 7" in length. The cichlids are all under 4". (most under 3").. I just finished setting up my 120 Gallon w/ a wet dry system and am waiting for it to cycle. I plan on having the new world cichlids and the pair of jewels in there and the BGK. I also wanted to add a clown knife, since that is the fish I was originally planning for anyway... Will there be a compatability issue?