Of all the fish on your list, the one most likely to be picking on him is the Dussumieri

Never kept this fish myself but the one thing that does come to mind - flow flow and more flow. I've seen this fish while snorkeling and it's plum happy in the raging surf at depths less than 10' and from what I've heard from those that seem to successfully keep this fish that the common element seems to be high O2 and high flow turnover and surging currents in the tank. In fact I have this recollection of Marie posting a picture (or maybe a video) of her Achilles tang doing a sort of "surfing" trick in the output of a Tunze ... (at least I think it was Marie.. apologies if I'm remembering wrong..)

So I'm thinking that even if the fish is in QT, it might not hurt to have a higher flow turnover in the QT tank than what you might do otherwise.

Just my $0.02, not based on experience at all, just based on my own speculation. Good luck, they are a beautiful fish, I hope one day when I'm ready, I can try this fish too.

any pics of Dussumieri Tang ???

It was me and it was a video. He looks so small and cute in that video.
I really need to get him a bigger tank he's showing signs that the 175g is becoming (is) too small :sad:
This was taken almost exactly 2 years ago

http://img.photobucket.com/albums/v2...achvid0007.jpg

He ain't small & cute anymore. He's big, fat & handsome.

Hey Marie, if your 175 is getting too small, maybe he should go in my 225 until you get the 300.:mrgreen:

Fow flow, we have two tunze 6200 on wavy seas and a dart for a return. The tunzes put out about 5800gph each and the dart about 2000gph. I thought that this was lots of flow for our tank which is 6'x30"x24". Correct me if I am wrong, but would that not be enough??

And yes the achilles loves swimming in the flow. It swims laps around the tank in and out of the rock work, stopping each time for a nibble of nori.

I was just down there for about 15 minutes watching there behaviour. When I first got down there, the achilles was quite grey. The longer I stayed, the better his colour appeared. However, it would sometimes go grey again.

With the Dussumieri, it is so scittish, I would highly doubt that it is doing anything to harrass the achilles. It definetly is possible considering they are both tangs and the dussumieri is a lot bigger, but knowing his personality I don't think so. To put it in perspective, when we recently added a 1.5" Sunburst anthias, the close to 7" Dussumieri tang was scared of it.

The toughest thing about these fish is getting them to eat. If they eat, eventually they will kick the ick that inevidably comes with them.

Assuming he keeps eating you should have no worries. If he is in QT, get him good and fat as it could be stressful him when there become competition for food.

Get him good and fat, so if he does not get to eat too much for the first few days his fat reserves do not go down to low.

I have tried the achilles tang on two occasions many years ago. In both cases the tangs died.
I read subsequently that the are a very very difficult tang to keep as others have posted. I think it is on the way out as the symptoms you described were the same as mine.
Although they are algae eaters I would add to there diet varied high quality foods including garlic and selcon supplements.
I do know that the require highly oxygenated water so I would suggest you install a wave system or at the minimum place a hefty powerhead six inches below the water line. You will see that the achillies will 'play' in the stream.
Best of success. I hope everything works out.
http://wetwebmedia.com/badacanthurusaq.htm has excellent recommendations on the good and bad tangs to keep. The achlilles tang is on the bad list.

Apart from the well know tank size requirements (which you easily meet), reefers are well advised to consult this list before considering a tang purchase.

Just a quick little update, the achilles seems to be doing better today. When I got home from work, I went straight down stairs to the tank. When I got around the corner I noticed him right away, because he was black again. YAY. Now he does still have a little bit of ick, but he is still eating a ton and has a big gut on him. Here's a couple pics I just took.

Here he is picking algea off the bottom of the tank.
http://i271.photobucket.com/albums/j...ishTank221.jpg

Here he is with his new little buddy, our new Sargassum Trigger.
http://i271.photobucket.com/albums/j...ishTank240.jpg

About the trigger, I just picked him up from Aquatics Addictions on Wednesday. I am thinking that maybe he is somehow making the achilles feel more comfortable now that he is the new guy in the tank. I don't really know, I am just happy that they are both eating and the achilles seems to be on the right track again.