2 goldfish questions

Question
8 months
11 gallons
Goldfish, Fancy Goldfish, and Platties
2 goldfish, 4 fancy goldfish, and 10 platties
pH 6.8, ammonia 0.25ppm, no nitrite test
change 5 gallons of water a week

One of our completely black fancy goldfish is slowly turning orange. First his eyes turned orange, then his belly, and now there are some spots on his sides.  These orange spots look like they might be areas that are missing scales. This fish has had this problem for over a month now, but seems pretty healthy in other ways. He eats well and swims normally. There are no signs of wounds or parasites. What would cause this and is there something we can do for him?  The tail of one of the white fancy goldfishes is always badly torn.  Why is this?  Our other two fancy goldfish are just fine.


Answer
Hi Charity;

Goldfish change color as long as they are growing and maturing. Especially the black varieties. It is rare for a black goldfish to remain black. Some even turn a bronze color or silver.  

The loss of scales and constantly torn tail are from the tank just being way overcrowded and causing chronically high ammonia. An established tank such as yours should have an ammonia reading of "zero" but with so many fish in there still growing and maturing you will never be able to keep up with it in such a small tank. Even if you changed water every day it's just too small. It's only going to get worse as your goldfish grow larger too. Those guys will get very large (6 to 8 inches) and each goldfish needs at least ten gallons all to itself. You might be able to get away with a 55 gallon for all your goldfish but you would need to graduate to a 75 or larger eventually. That's why they are often kept in outdoor ponds. They get the space they need to grow and just be their naturally messy selves. Here is a good web page about them;

http://www.firsttankguide.net/goldfish.php

Here are some pages about stocking your tank and fish sizes;

http://www.firsttankguide.net/capacity.php

http://www.firsttankguide.net/size.php

I hope they feel better soon...

At Your Service;
Chris Robbins