please look at this real quick...

[sduerk]

My yellow tang has been in quarantine for almost two weeks now and is now showing a very pronounced white stripe down the length of his body. What is this and should I be concerned. It has become more white for the last couple of days but is now Very white.
Someone in the other forum said it could be HLLD. It is a very solid white line.

 

[beth]

Is the "stripe" along the fish's lateral line [which is located from gills running toward the tail in a slight arch near the top part of the fish].
Where is the stripe? Take a close look at it. Does it look like the yellow tissue has eroded away exposing the white tissue beneth?

 

[sduerk]

well i took a real close look at it with a very bright flash light and it looks like it starts behind his gills and continues about 2/3 of the way to his tail and stops. It does not look like the tissue underneath has been exposed but he is still covered in ick. when i had the light on him you could see the ick all over like little grains of salt on him. What do you think? I'm doing hypo and the sal. is around 1.010.

 

[beth]

Yellow tangs naturally have a white line that runs the length of their body. The line looks normal. HLLE, head and lateral line erosion, can also look like a white line, but the line is not even, it will have rough edges and it tends to arch over the fish's lateral line, which is more toward the upper part of the fish's body. If you look very closely with a magnifying glass, you can see the rough edges, and tell that the tissue has actually eroded exposing white tissue beneath. The normal white line seen in tangs is a nice, clean edged faint line running thru the middle of its body.
Sounds like your fish does not have this problem.
To effectively treat the ich your fish has, you must drop the SG to 1.009. Don't use swing arm hydrometers to get this measurement as they are totally inprecise. You can use a glass hydrometer.