Bubble eyed goldfish w/red tail end

Question
Hello,

I have a 20 gallon tank for a bubble eyed goldfish and he has been healthy for the past two months; however, lately his body near the tail has turned red from the previous golden color. This difference in color seems to extend all around this quarter of an inch part of his body. In addition, he has been staying at the top of the tank recently although there is proper filtration and an air pump. Are these changes in behavior and color normal?

Thank you,
Alex

Answer
Hi Alex,
Bubble-eyed goldfish come in many colors, ranging from a pale yellow to a deep red. As the goldfish ages, it may change color slightly. This red color may be natural, as long as it does not look inflamed or bleeding. However, you said that he is staying near the top. If the affected area seems to be infected, it may be a bacterial or viral infection. Here's a good link to diagnosing fish disease:
http://www.fishlore.com/Disease.htm

Once you have diagnosed the disease, buy an appropriate treatment, (available at any fish store). Then, I would take the following steps:

1) Change 20% of the water daily or every other day,
2) Gravel vacuum along with the water change,
3) Remove carbon from filter,
4) Add an extra airstone during treatment,
5) And treat with the medication, following directions carefully.

I hope this helps, best of luck to your goldfish!