Hello everyone I am wondering if I can get some help and understanding what is going on with my fish tank. My frogfish died out of nowhere.(I had him for 3 months) His tail turned white and the same day he died also with labored breathing. I waited a month and put another frogfish in and he died to the same exact thing his tail turned white and he started breathing hard and died. I am scared to put anymore fish in my tank and I do not know what's happening. Also before you ask, I have tested my parameters and found nothing wrong there. Also I noticed that when they died their tales were like sliced up and rotten. I'm posting a picture to show what his tail looked like before he died, it almost looks like slime on his tail.