during a water change in my 100 gal tank, I noticed one of my angel fish had blanched completely.?

Question

WhAT DOES LOSS OF PIGMENTATION MEAN IN ANGEL FISH? How should I treat it to get its colour back?

Answer 1

That could be a stress reaction from the water change. Give it a day or two and see if it's normal coloration returns. As far as diseases, there are several things that could cause partial color lose, but total color lose would be very rare indeed so I would assume it's related to the water change from the information you provided.

MM

Answer 2

There are a few factors that can come into play here. For example, is the color change still evident?

Many fish, angelfish included, can change their colors slightly during times of stress or excitement. Oftentimes the color returns to normal when the cause is eliminated. I have a large tank with angels and a few of them are instantly diluted when water changes are done. Once the tank is no longer disturbed however, they go back to their normal color.

On the other hand, when they are overly excited (during feeding or breeding) their colors are strikingly darkened.

Other factors might include changes in temperature and water parameters so be sure to keep an eye on all water levels (ammonia, nitrite and nitrate) to be sure the fish isn't being stressed by something potentially fatal.

Answer 3

I agree with MM, sounds like it was stress from the water change. How much water did you change out? Could've been a temperature difference or ph difference, did you use a dechlorinator if needed? Should go back to normal color within a few hours to a few days, depending on what stressed it out.