I had a long-horned cowfish in my 55 gal
about 15 years ago and it did just fine in the fish-only tank. Of course back then I didn't know what fish were compatable with what, so I just bought what I liked and waited to see if they got along. If not, the aggressor would go back to the LFS
. In with him, there was: lion fish, seahorse, powder blue tang, small dog-faced puffer and a coral beauty. Along the way there were others, like a trigger that lasted a day before I returned it and some damsels. I had the cowfish for about two years - then my brother cought the house on fire and since there was no power, I had to sell the survivors to the LFS
. The cowfish was one of my favs, though. He would recognize me in a group of people and come hovering over to where I was. It was so cute!