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Fish/Betta going through thermal shock


Ron, We had drastic weather change today which effected the temperature in my room and caused the water in my betta's bowl to drop to 60 degrees. I was so worried about him because he was lethargic and wouldn't eat, but I wasn't sure how to fix it. I bought heater, changed his water then added him back to the bowl(keeping the temperature the same during the switch). I'm not sure if the heater worked too fast because after the temperature started to rise he seemed to freak out and floated to the top on his side. Is there anything I can do for him to help him out of shock? Also his long fins went down in size. Does that mean something else? Blerg... Thank you for any advice!

Hi Erin,
  Rapid temperature changes can be quite challenging on fishes, particularly fishes like bettas. At this point, I don't think you should do anything more. It is up to him and the less you fiddle with him at this point the better.  For future reference, if a fish gets cold, you need to warm it up VERY slowly, as in over a day or more. In many ways, it is the change in temperature which is more harmful than the absolute temperature value.
 Let's hope he is a strong little fighter.  He may have some fin damage, but that generally grows back rather quickly.   

-- 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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