My Chinese algae eater turned golden. Is this color change normal?

Goldfish naturally change color as they age. Though most do so during their first year or two of life, others change throughout their lifetime. There are two different types of color changes in fish: physiological and morphological. Physiological changes occur when the pigments in the cells either spread out, which makes the colors more pronounced, or when the pigment clusters in the center, which makes the colors more muted. Morphological changes occur when the actual number of pigments in the cells increase or decrease. An example of a morphological change is when a black goldfish starts to turn orange or a young goldfish loses its black markings as it ages. In this case, as the fish matures, it’s losing its black pigment cells. How and when their colors change really depends upon their individual genetic makeup. I would not be overly worried if he is acting otherwise normally.

Thank you for the picture - I am unable to tell if the tail is just turning transparent, or if portions of it are missing. If it is truly just a color change, and there are no other problems with C.G. or the other fish, it may just be that he is going to become a different color. If the tail has missing portions, that is more likely to be caused by an infectious problem (such as bacteria, fungi, parasites). I would recommend evaluating your water quality parameters, as you eluded to in your question. Then I would monitor the tail, and if there are portions missing, I would recommend having him evaluated by a veterinarian. They can take samples of the area, as well as from the skin and gills to evaluate for parasites and other organisms.

Add some protein to his diet. This can be in the form of live, frozen or freeze dried blood worms or blackworms. You can also use your preferred search engine to look for "earthworm sticks" to feed him. Check the water quality as well (hardness, pH, etc.). Make adjustments as needed. Low water temps may cause stress and illness. Check your tank heater and temperature.

Thanks for your question about your fish, and congratulations on your new family members! I didn't see how recently the tank was set up, but there are a couple of things that could be going on. I would start by checking your water quality - any abnormalities in water quality can make fish have abnormal behaviors, and the water looks a bit murky in the photos you provided. There may be parameters that need to be addressed depending on what you find. If you do not have a water quality kit, they can be purchased at the pet store or an aquarium store, or you can take a sample of your water in for evaluation to these places as well. Some will charge a small fee for this service, just so you are prepared. Also, with recent tank set ups, it can be stressful for fish as they are in a new habitat. I would recommend keeping the light on for only a few hours per day to start, as the bright lights can be shocking for them (since fish don't have eyelids). Gradually you can increase the length of time that the lights are on so that you reach a cycle of 10-12 hours of light and 12-14 hours of darkness for them. I hope this gives you a place to start, and I wish you and your mom the best with the new pets!

Thanks for reaching out about Corn and including photos. It appears as if this is a type of algae. Try washing in hot water. Overgrowth of algae can potentially cause some problems and foul water quality. Algal overgrowths often associated with too much sunlight. Good luck.

The color change may be due to the illness or stress. Perform partial water changes, no more than 30% at a time, and monitor the fish. Consider adding an airstone since this medication can affect oxygen levels in the tank further contributing to stress.

Hi Emma. Pucker looks fine. There is a little difference in the before and after images. This could be due to diet or water quality/chemistry. Continue to monitor him and feed the color enhancing pellets. Maintain pristine water quality via filtration and regular partial water changes. Symptoms that may indicate a problem include lethargy, loss of appetite, clamped fins or difficulty swimming.