Muelleri Butterfyfish - Parasites or Tank mates causing frayed fins?

[tylersarah]

As it reads...

Info:

187G reef with Bristletooth tang, Tinkeri butterflyfish, Melanurus and Pygmy wrasse & a Percula clown pair.

I've had the Muelleri for years and have seen no other parasitic symptoms develop over the course of at least 6 weeks since the frayed fins were noticed. The gills are functioning normally, no white spots, head shaking, clamped fins, darting, flashing etc. I have noticed over the past couple months the fish is getting increasingly less aggressive during feeding - I feed 2-3x/day and direct food (fresh seafood/Larry's Reef) to the Muelleri while actively warding off others. My first theory is that something is wrong internally and other fish are picking on him. It would explain the lack of enthusiastic eating and no other ectoparasitic symptoms, but I have yet to witness a fish bite him.

I also see a scale is raised on the Muelleri and on the tang, a minimally torn corner of the tail fin. Could Melanurus be responsible for the fin damage? Or even more plausible, the breeding perculas? The female surely isn't shy about biting me! I haven't witnessed any aggression and when observing, the fish don't seem to avoid or agitate each other.

My other thought is bacterial, although, I would expect some slime, or discoloring of the fins etc.

Back to parasites. While they're always suspect when I see frayed fins, I do maintain a tight regime: all fish go through TTM, at least 7 wk quarantine, Levamisole and a fw dip prior to display entry. Everything wet goes through 12 weeks fallow in a qt. And this has been observable for at least 6 weeks with no added symptoms, so I tend to lean away from this possibility.

Thoughts welcome. I've been observing and hoping the pieces fall into place, but so far coming back to square one.

Sarah

 

[Deinonych]

Given that you have a rigorous QT regimen, my bet is on aggression from the clownfish. Wrasses don't occupy the same ecological niche as tangs and butterflyfish, so it's unlikely the Melanurus is the culprit. Clownfish will defend their territory pretty aggressively, especially if they are actively breeding (not sure if yours are). I have a breeding pair of Ocellaris clowns and the female is always sparring with my Kole tang. I never see any actual fighting, but the Kole will have bite marks on his flank every now and then, and recently the female clown acquired a jagged tear down her dorsal fin that looks like a scalpel strike. The female has also taken a large chunk out of my foxface's caudal fin in the past (that took months to grow back).

Bacterial infections on fins look different than the picture. Usually there's a margin of erosion with a white boundary. Your picture looks like fin nips to me.

 

[ThRoewer]

Looks like aggression - as Chris stated, bacterial infections look different. Bacterial infections cause the fin to get milky and the end often look thickened at the end.

 

[tylersarah]

I agree with you guys, thanks for the consensus.

I found an adopter for the clown pair (breeding yes) with a dedicated anemone tank.