Only my Tangs get ich. No others. Why?

[tbone28]

Whenever I introduce a Tang, it gets ich. But all my other fish are OK. Why is that?

My other fish include Bartlett's Anthias, chromis, firefish, diamond goby, lawnmower blenny.

I've introduced several tangs, and all have come down with ich.

My acclimation procedure includes 30 min bag float, then I open the bag and pour small parts of tank water every 10 minutes for another 30 minutes.

I initially introduced a Desjardini, who was fine for 2 weeks, then developed ich and died in 2 days. I waited 2 months before adding any other fish. I then introduced a PBT, and again ich developed within the 1st week. This time, I waited one month, and introduced another Sailfin. Again, ich within the 1st week.

Any thoughts as to what's going on?

My tank parameters
180g (~240g total volume)
Temp 78-79

[Radioheadx14]

Tangs are VERY prone to ich. Also once ich is in a system with fish, it can stay in the tank indefinitely. Even though your other fish have no signs, they still allow ich to reproduce in small numbers. When a fish is added its very stressed from the capture, transportation and acclimation. Maybe you should look into quarantining your new fish for 2-6 weeks.

Also if they die within a day or so, it might not be ich, it might be velvet. It attacks very fast. Ich is a b****! Once its in your display, there is not much you can do besides taking all the fish out for 6 weeks and treating the fish. Allowing the tank to go fallow for 6 weeks will kill the ich because they wont have a host to reproduce.

Its a pain in the *** but there isnt much else to cure the problem.

[tbone28]

Thanks for your explanation. I lost the 1st sailfin in a couple of days after seeing the white spots. The other tangs hung around.

What are your thoughts on those "reef safe ich medicatons"?

for example:

http://www.marinedepot.com/ps_AquariumPage~PageAlias~medications_ruby_reef.html

[Radioheadx14]

There are no reef safe medications that i know of... trust me, i have looked into them. they are either snake oil or stuff dies. The only things that really 'treat' ich is hyposalinity (sg = 1.009), copper based meds and formalin.

Corals cannot take hyposalinity and copper based meds are toxic to all things (even fish to an extent.) Plus using copper in a tank with live rock or sand is bad news. the rock absorbs the copper and will leech it out for a long, long time. Tangs also don't react well to copper.

If everything is fine now... I would either wait a while to add new fish or remove everything and treat.

[tbone28]

Everything is looking good now. Just want to "prepare" for the next time I add a tang. So it sounds like those Ich medications that say they are safe for coral is just snake oil? They're safe cuz they don't kill the ich?

Thanks for your help :)