Originally Posted by mr_X
Well, if you added the eel and it hasn't died yet and you didn't do massive water changes and run carbon to remove the toxin, then we know it wasn't the slug.
+1. Housing a black ribbon eel is questionable even in an established tank let alone a new tank. Id suggest slowing it down a bit and doing alot more research before attempting to establish your sw
hobby. Between the questionable rock, new tank, and lionfish death, it seems you may be traveling down the wrong path