ick or bacteria? how can you tell?

[henrystyle]

Here is my problem.
I have a 120g with 12 green chromis and 1 sailfin tang in it. After adding the tang to my system, I began to see white spots all over the tang. The chromis were perfectly fine with no spots or signs what so ever. I took the tang out and put it in my 30g with other fish and within 3 days all the spots were gone completely. No medicine, no nothing. I did a large water change on the 120g and decided to put the tang back in. After a few days the spots came back on the tang again. Chromis were still fine. Now I'm wondering if it is actually ick thats causing the spots. Wouldn't the chromis be affected as well if it was ick? What about a possible bacteria infection? I also have no room for a quarantine tank.

All these problems started when I stopped running those eco-bak bio pellets. I believe that gave me a bacteria outbreak.

 

[Jacob D]

It's always difficult, if not impossible to give diagnosis over the internet. It sounds like "Ich/Ick" from your description and with Tangs being prone to Ich when they're stressed that makes it likely to be what you're seeing. Due to the lifecycle of Ich it's not unheard of for people to claim to have cured it naturally, or it "just went away"... this is usually not the case, it's just the progression of the lifecycle, which usually results in it "coming back again" although it never really went away - just like you're seeing.

There is some good reading here:
http://reefkeeping.com/issues/2003-08/sp/index.php

If it is Ich, it's a pretty good bet that all of your fish will be infected eventually, if they aren't already.


BTW, the bacteria you're talking about with the Eco Pellets (etc..) is not of the sort that is harmful to fish. It's a "good bacteria" like what you have in your live rock.