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My Betta fish is lethargic, barely eating, and has raised scales. Why?

Updated on September 23rd, 2025

Pet's info: Fish | Unknown - Fish | Male | unneutered | 10 months and 6 days old

My male Crowntail Betta fish is acting very lethargic, he stays at the bottom of the tank and only coming up for air, barely eats, his stomach looks hollow, and the scales along his back are raised. He has been this way for a few weeks but isn't getting better. I change his water weekly, and he lives in an environment where his is not caused stress.

4 Answers

Most Helpful Answer

Angel Alvarado, LVT

Answered By Angel Alvarado, LVT

Licensed Veterinary Technician

Published on December 4th, 2016

Check the water quality. This can be done with a home test kit or you can submit a water sample for testing. Most pet stores or aquarists will do this for free or for a nominal fee. Correct any imbalances as indicated. Check the water temp as well. Aim for 78 F to 80 F. Use a tank heater to prevent temps below 74 F.
Offer a good quality pellet such as Hikari BioGold. You can also feed blackworms or bloodworms. Live worms may get him eating. Freeze dried tubifex worms may also stimulate his appetite.
If there are no outward signs of bacterial or fungal infection, consider parasites. You can use metronidazole for fish. It is sold in most pet stores in the aquarium section. Follow label directions and gauge his response after treatment.
The raised scales are a concern because that can be a symptom of dropsy. Dropsy is common in bettas and usually fatal. It is typically accompanied by a swollen abdomen though. Fish tuberculosis is another serious concern. This is a slow, progressive illness that can kill fish and ruin tanks/bowls.
Start with the basics as listed above. Try water changes with conditioned water and offer different foods to get Thorin eating. You can request a consultation to discuss his condition in greater detail and for additional resources.
Vote Icon1Pet Parents found this answer helpful

Related Answers from Veterinarians

  • Answered By Angel Alvarado, LVT

    Licensed Veterinary Technician

    Published on July 27th, 2018

    Check the water chemistry and quality. Use a home test kit or submit a water sample for testing. Elevations in ammonia or nitrites can be toxic to fish. Perform a partial water change, if indicated, until ammonia and nitrites are at 0 ppm and nitrates are at 20 ppm or less. Use only conditioned water that is temperature matched to prevent stress or shock. Bettas are tropical fish and do best between 78 F and 80 F. Low water temps can also affect appetite and activity. Provide plenty of cover for him to hide in and around.

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    1Pet Parents found this answer helpful

  • Answered By Angel Alvarado, LVT

    Licensed Veterinary Technician

    Published on December 30th, 2017

    Check the water chemistry. Elevated ammonia or nitrites can drive her towards the surface. Perform a partial water change daily to stabilize chemistry and maintain water quality if indicated. Use only aged or conditioned water that is temperature matched to prevent further stress or shock. Bettas do best between 78F and 80F. Plain aquarium salt (NOT table salt) can be used as a general tonic to reduce stress, improve gill function and aid in any recovery. Dissolve 1 teaspoon of salt per gallon of water in a cup of tank water and gently pour it into the tank. Treat for 10-14 days then reassess the condition.
    These steps should get her eating again. If not, try soaking the pellets in some garlic juice to stimulate the appetite and provide an immune system boost.

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    1Pet Parents found this answer helpful

  • Answered By Angel Alvarado, LVT

    Licensed Veterinary Technician

    Published on July 22nd, 2018

    Check the water chemistry and temperature. Use a home test kit or submit a water sample for testing. Most pet stores will do this for free or for a small fee. Aim for 0 ppm ammonia and nitrites with nitrates at 20 ppm or less. Perform partial water changes, no more than 30% total volume at a time, to stabilize chemistry and improve water quality. Use only aged or conditioned water that is temperature matched to prevent stress or shock. Bettas are tropical fish and do best between 78 F and 80 F. You may need a small, submersible water heater to maintain temperature.
    Feed either the pellets or the bloodworms at one meal. Offering both is too much and he likely won't eat it all. Any uneaten food will rot in the tank and foul the water.

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    1Pet Parents found this answer helpful

Smart Picks for Smart Questions

Training & Behavior
My Betta fish isn't eating. What's wrong and how can I help?
Check the water temperature first. Bettas are tropical fish and do best between 78 F and 80 F. Next, check water quality. This can be done by using a home test kit or by submitting a water sample for testing. The local pet store may do this for free or for a small fee. Aim for an absence ( 0 ppm) of ammonia and nitrites with nitrates at 20 ppm or less. Perform partial water changes if necessary. Use only conditioned water that is temperature matched to prevent stress or shock. Offer an appropriate diet as well. Bettas are carnivorous, so make sure the flake or pellet is not mainly vegetable matter. Hikari makes a great Betta diet in pellet form. You can also offer blood worms, shrimp or Daphnia to add variety to the diet.
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My betta is wiggling, not eating, and seems sick. What's wrong?
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Why is my betta fish at the bottom, barely moving, and breathing hard?
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My betta fish has black, short fins, isn't eating. What should I do?
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Why is my betta sick, lethargic, and has white spots? What can I do?
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My betta fish is lethargic. What should I do to help my fish?
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