iridescent sharks turnin white and pale.

Question
QUESTION: hi david,
i have a 120 gallon tank.well filtered,but i notice taht one of my iridescent sharks turning white and it has been remained that way for a week or so.i'm totally confused!!!!!!!!is it fatal for my shark?
help me out,
thanks,
anush

ANSWER: Hi Anush:  I can not answer this question with out some further information.... water chemistry, temperature of the tank water, and a better description of the shark... white in skin color? Trailing strings that look like cotton? etc.




---------- FOLLOW-UP ----------

QUESTION: hi dave,
well it was black in colour(but now its not).the ph is alright.and the temperature is 24degrees .other2 sharks are alright(that is they are black).they are about7 to 8cm in lenth.help me out!
thankin' you,
anush

Answer
anush:  It is impossible for me to help you with your shark if you can not supply me with a better description of its condition. So please take a few minutes and study your shark... and then write me a very accurate description of what it looks like.  I am looking for information that will help me determine if it is a disease or possibly a genetic change that may be part of its growth... dave