Color changes in catfish can be caused by different factors which could be harmful or harmless depending on what actually caused it.
But, the most important thing is that we should be able to identify correctly what makes our fish to change color. I will like to highlight on that a bit.
Cryptic coloration could be as a result of the container you put your fish most especially younger ones. They blend to the background color of the container thinking that predator or any disturbance won’t be able to see them. It is one of their strong adaptive features. So, if you put your fish in white container and the color changes to whitish gray, don’t panic your fish are OK.
There can also be change in color if there is a physiological stress on your fish. You will notice this if you’ve stressed fish over long time , they tends to change to whitish grey as well and if there is no prompt intervention, they usually die. The stress can come from anoxic condition (no oxygen) or fish that jumped out of the container or any other thing that can induce stress.
Color can also change by nutrition , in this case ,one has to be very careful as the change in color may be an indication of bad substance in the field or excess pigment material which would not have any negative effect in the fish. The key here is to know which one is really changing the color of your fish. The color usually changes to spotted brown in this regard. I’ve once change a fish meal which changes color of my fish , I didn’t know where the issue came from at first until when our customers who used the same batch of the feed started calling that the color is changing as soon as they started feeding the feed. But, the good news was that it didn’t affect them in any way, they grew normally and no pathogenic effect.
Sudden variation in water quality parameter such as temperature and DO can also change the color of fish.
Change in color could be a response to pathogen invasion. It could be regarded as one of the clinical signs in fish diagnosis. If your fish in earthen pond for instance start changing color and you’ve not changed feed recently and no stress has been induced, it could be a sign of diseases presence. Meanwhile, this kind color change will be associated with unusual slow response to feed, sluggish movement,hanging at the pond bank,gasping or rubbing their body at the pond.