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Fish/Bug Eyed Goldfish


I somehow inherited a black bug eyed goldfish a couple of years ago and everything has gone well until the last few days.  I noticed a couple of days ago that one eye appeared larger than the other. It seems to have swollen more and today that side of his face is all swollen and looks like it will pop.  Anything I can do for him?
He is alone in the tank, never comes in contact with other fish, and I have not changed anything in his diet, the tank filter system or anything else.

Thank you for any advice.

Hi Carol,
  Unfortunately I am no expert on goldfish, and in particular on some of the more bizarre forms, so I cannot answer your question directly. Have you been doing regular weekly water changes? Ideally, you should be changing 25% of the water in his tank once a week, every week to keep him happy and healthy.  That is the single-most important thing you can do.

-- Ron C.
  Cichlid Research Home Page <>


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Ron Coleman


I am an expert on cichlid fishes, particularly New World cichlids. My broader expertise includes the behavior, ecology and reproduction of fishes in general. (I am NOT an expert on Goldfish). Please do not use abbreviations, such as "my GT has a swollen eye" because I don't know what a "GT" is. The more clearly you can explain your question, the better chance I have of understanding what it is that you seek. I keep fishes both as a scientist and as a hobbyist and I currently maintain about 140 aquariums.


I am an Associate Professor at the California State University, Sacramento in the Department of Biological Sciences, and I run a website, called the Cichlid Research Home Page . I also write for many popular aquarist magazines, and I was editor of Cichlid News magazine for several years. I am a scientist and I spend my time teaching fish biology, ecology, behavior and evolution and doing research on the reproductive biology of fishes, particularly cichlids. I do research in the laboratory and in Costa Rica, Nicaragua and Mexico. My main interest is understanding the evolution of parental care in fishes. I am interested in encouraging greater public awareness, understanding and participation in science.

Cichlid News, Tropical Fish Hobbyist, Freshwater and Marine Aquarium, Science, Behavioural Ecology and Sociobiology, Copeia, Canadian Journal of Zoology, Trends in Ecology and Evolution, AUK, Environmental Biology of Fishes

PhD (Toronto, 1993) MSc (Simon Fraser, 1986) BSc (British Columbia, 1983)

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