ID Please

[Demeter]

I'm not sure if these are blotches on my tangs dorsal fin, but I think it may be something different.

This has been about a week. He's been rubbing against the rocks lately.

 

[leebca]

You didn't post enough information. For instance, if this was a recently acquired fish, the condition might be from a net, capture, or other transportation injury.

If the fish is an 'old' pet, it may have had a run-in with a piece of rock, decoration, or coral. Tangs are not the 'sharpest knife' in the drawer and in their all-too-often mad dashes, they run into things. It looks like this guy forgot to duck.

Another possibility is the onset of a bacterial infection brought on by either a chronic or acute stress source or sources. In this case, if it gets worse or spreads, move the fish into a hospital tank and give it a treatment using an antibiotic.

In all of the above scenarios, the fish is irritated. Flashing or 'scratching' might be a normal response to this condition.

 

[Demeter]

Thanks for the info. I've had the tang for about a year. I did just add LR to the tank to maybe he should have ducked instead of dodged. I'll keep an eye on him to see if the possible infection spreads. Are the medications that treat infections, " 2 tablespoons per 10 gallons", safe for corals, etc.

Thanks

 

[leebca]

I don't recognize that particular medication instructions. Sorry. I stick with antibiotics and don't attempt potentially less effective meds.

Several studies on "reef safe" products show that they often kill something. I prefer products that specifically list the reef specimens they are safe with and hopefully tested with, by the med manufacturer.