yellow tangs dying-black spots

Hi all, wondering if anyone has had this issue. 90 gallon mixed reef. have lost 2 separate yellow tangs to what looks like ich but its black. All other fish, wrasses, clowns, damsels are unaffcted. The first one died amonth ago. 2 weeks later I got another yellow tang and he got the same thing and died. All parameters are in check. Just wondering what the frick is happening? Thanks in advance

Was just looking back on my notes...

Tangs are the most susceptible. Other fish can get them, but it's less common (some fish seem immune to them).

The freshwater dip should be about 8 minutes, but I've had 5 minute ones knock them off. I'd use methylene blue with the dip, but that's just me.

Placing the tang back into your system will likely cause a reinfection. If no other fish are showing signs of the worms, then you may just need to keep the tang out of the system for about 6 weeks.

If I were in your shoes, this is what I'd do...

Give the tang an 8-minute freshwater dip in methylene blue. If you need help doing the dip, let me know. It's easier than it sounds, but it's easy to mess up too.

Place the fish back into the system, but dose PraziPro (reef safe, but it will kill worms like feather dusters, etc.) Hopefully the Prazi will knock out any remaining worms in the system. Prazi will kill some of the worms on the tang, but it's not nearly as effective as a freshwater dip. Just make sure to have some water change water ready...sometimes Prazi will cause some issues if you have too much worm dieoff.

Aw, sorry.

I would dose Prazi, especially if you've never done it before. It'll wipe out any internal parasites too,so you'll probably notice your fish will get fatter.

Because of black turbellarian worms, velvet, and uronema, I always freshwater dip fish for about 5 minutes when I first get them. It's so easy and works so well! I'd do it especially if you don't QT. It won't help with ich, but it's a good start.

Is the Prazi expensive?