Black Moor Eye Closed

Question
Hi, I have a 12litre tank with two gold fish and a black moor. I woke up this morning to find that my black moor has one eye permantly closed. Apart from this it is feeding and swimming well. What could be the cause of this.
Thank you Angela.

Answer
Hi Angela;

Goldfish don't have eyelids, so could it be that the eye is infected and/or covered with fungus? What color is the outside of where the eye is supposed to be? This could be an injury from fighting or scraping on something in the tank.

Or, is the eye just gone? If the eye is gone, that side will look more flat or indented instead of round and protruded like the other.

The fish are actually in too small a tank. They are too close to each other and may be hurting one another and/or are bumping things in the tank. It could also be infection caused by excess waste from the overpopulation of fish. Goldfish grow to be 6 to 8 inches and need a lot of room to grow and thrive. I wouldn't keep them in anything less than 20 gallons (about 80 liters). They are deep-bodied messy fish that need plenty of room to grow and thrive. When they are crowded, they become sick easily and develop infections. The more dominant fish in the tank will pick on weaker ones and sometimes kill them to make room for themselves. It is a natural response to an unnatural situation.

Make plenty of water changes to help the fish heal. Remove 25% twice a week to keep the water clean. You can also add uniodized aquarium salt to help the fish recover and weaken harmful bacteria and fungus that may be growing in there. The proper dosage is 1/2 teaspoon per gallon of water. I can't remember the metric equivalent, so hopefully you can convert it yourself. (sorry) Add more salt again when you make water changes, but only for the water you actually replace. For example, if you remove one gallon of water, add back 1/2 teaspoon to the tank to treat the new water. This keeps the salt concentration the same all the time. And.....shop for a bigger tank! The fish will be so much happier in larger quarters. More room to move and exercise and cleaner water, they will grow, become more colorful and much, much healthier.

Followups welcome

At Your Service;
Chris Robbins

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