Help required ASAP...

[elted]

Hello all,
I have a 100 litre tank With some LR and a Eihem external filter, 2 powerheads, various snails & crabs (inc a huge arrowhead crab), and up until last week: 4 fish. The tank has been up and running since 1998! with no problems.
Last week I lost a young Clown, and a Damsel, whats left are a mid sized Blue Tang, and a Longhorned Cowfish. The Blue Tang keeps scratching its self off a rock and the cowfish has some white gunk completly covering one of its eyes. I got a Cleaning Shrimp yesterday in the hope of some help?? If my poor cowfish looses his other eye he wont be able to feed.
PLEASE help.
P.S. All water Paramaters are fine.

 

[quarryshark]

First of all, welcome to AA.
Do you own a qt tank? If so I would remove them to it. You very well may a parasitic outbreak in you tank.
Have you added any livestock, LR, sand, anything recently?
Also what are you water parameters?
Keep an close eye on the cowfish, not sure if you are aware that they emit a toxin when they die that could possibly wipe out your other livestock.

 

[srgetz]

Any symptoms on the clown and damsel? Anything visible on the tang like white spots? Do you mean cloudy white on the cows eye? Is there a skimmer on this tank and when was your last water change (and how much)? That is a very high bioload for 100L.