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Why is my betta fish lying at the bottom and its fins changing color?

Updated on September 23rd, 2025

Pet's info: Fish | Betta | Male

Hi, I have a beta fish named Patron and recently he's been acting different. I noticed a few days ago that he has been laying at the bottom of the tank and only moves when I move him (he flaps his fins around a bit) but doesn't swim. I'm also really concerned because the color of his fins changed from red to an aqua. I've been thinking of possible reasons to why this might be happening and recently we started feeding him flakes instead of pellets or his water might be a bit too cold? Thank you

2 Answers

Most Helpful Answer

Angel Alvarado, LVT

Answered By Angel Alvarado, LVT

Licensed Veterinary Technician

Published on March 1st, 2019

Cold water can affect activity in fish. Bettas are tropical fish and do best between 78 F and 80 F. Check the water chemistry also. You can use a home test kit, such as the API Master Kit, or submit a water sample for testing. The local Petco may do this for free or for a small fee. Aim for an absence (0 ppm) of ammonia and nitrites with nitrates at 20ppm or less. Perform a partial water change if necessary to stabilize chemistry and/or to improve water quality. Use only conditioned water that is temperature matched to prevent stress or shock.
Diet can influence color, so it is possible this is partly to blame for the color change. There are diets that can be fed to enhance colors.
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Related Answers from Veterinarians

  • Answered By Angel Alvarado, LVT

    Licensed Veterinary Technician

    Published on May 13th, 2018

    Bettas, and fish in general, may lose color due to old age. At 2 years of age, your fish is getting old. Their lifespan is between 3-5 years, average is closer to 3 though.
    Maintain pristine water quality. Test the water chemistry to confirm an absence (0 ppm) of ammonia and nitrites. Nitrates should read 20 ppm or less. Partial water changes can be done to stabilize chemistry and maintain quality. Use only aged or conditioned water that is temperature matched to prevent stress or shock. Bettas do best between 78 F and 80 F.

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    1Pet Parents found this answer helpful

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