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Fish/Tiger Oscar acting strangely


hello I am a proud owner of 2 full grown Tiger Oscars the oldest is about 4-5 yrs old and all of a sudden has been swimming vertically with head always facing the bottom of the tank,he seems to be acting otherwise normal,he will come to me when I approach the glass and is interactive with the other younger Oscar(2yrs old)he is also eating, this has been going on now for the past 5 days I, upon examination I actually see that he is slowly getting worse,however his colors,scales,gills and fins are all in excellent condition....DO YOU HAVE ANY IDEA WHAT THE HECK IS WRONG WITH HIM??   

Hi Paul,
 Hmm... that is hard to say.  First, do you have sand or gravel or something on the bottom of the tank, other than just the glass.  If there is nothing there, then the fish's reflection really bothers some fishes. Assuming that is not the problem, then it is hard to say. If he were listing to one side or the other, I would be more worried because that would indicate a swim bladder issue, possibly an infection. I guess, from your description, I am not sure that there is anything actually wrong with him.  Oscars do some strange things at times.

-- Ron Coleman
  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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