How to Tell if Your Fish Is Dead

Co-authored by Lauren Baker, DVM, PhD

Last Updated: April 26, 2024 Approved

VIDEO

You see your fish floating on their side in the aquarium or notice that they jumped out of the tank. While your first reaction might be to grieve or start to dispose of the body, your fish might not be dead. You can take measures to know one way or the other by checking your fish's vital signs, dealing with a dead or dying fish, and considering other issues in fish who only look dead.

Method 1

Method 1 of 3:

Checking Your Fish's Vital Signs

Download Article

Look for signs of struggle as you place the net around the fish's body. If your fish is just sleeping, they'll wake up and try to wiggle their way out of the net. If they don't, they could be dead or very sick.
Check the gills for most species. If they're not moving, the fish isn't breathing. Bettas and other labyrinth fish breathe through their mouths. If your fish is from this family, watch their bodies for up and down movements.^{[1]
X
Research source}

Advertisement
3
Check the fish's eyes. Look at the eye as a whole. If they're sunken, your fish is dead or near death. Look for cloudy pupils, which is also a sign of death in most aquarium fish.^{[2]
X
Research source}
- If your fish is a pufferfish, walleye, rabbit fish, or scorpionfish, occasional eye cloudiness might actually be normal. However, you should contact your vet if the cloudiness persists for several days.^{[3]
  X
  Research source}
Do this if your fish has jumped out of the tank. Look for cracking of the skin as you pick up the body. Feel the body to see if it has dried out. These signs are only present in dead fish.^{[4]
X
Research source}

Method 2

Method 2 of 3:

Dealing with a Dying or Dead Fish

Download Article

Look for symptoms such as an inability to eat or sinking immediately after swimming to the top of the tank. This will be difficult to watch, but you should treat your fish like any other companion animal. Sit by the aquarium. Talk to your fish, if that's what you usually do.
Clove oil is a sedative and is the most humane way to end the suffering of a dying fish. You can buy it in most drug stores. Place only the dying fish in 1 litre (0.26 US gal) of water. Add 400 mg of clove oil to the water. Within 10 minutes, the fish will lose oxygen and die peacefully.^{[5]
X
Research source}
3
Remove any dead fish from the tank, if you can. Use an aquarium net to scoop out the dead fish. If you can't find the body, don't worry. The body itself won't harm the other fish and will decompose naturally.
- Fish parasites and diseases require living hosts. If you think your fish died of a disease, their tankmates might already be infected. Monitor them for symptoms. If they don't look sick or develop symptoms after a few days, they were strong enough to fight off the disease.^{[6]
  X
  Research source}
A dead fish flushed into a non-native habitat could harm native marine life. Dispose of a dead fish in the garbage or bury them outside. If the fish is large, burial is usually best. Check your local laws to make sure they'll allow you to bury a pet fish.^{[7]
X
Research source}

Method 3

Method 3 of 3:

Assessing Other Possible Issues

Download Article

1
Treat constipation with deshelled peas. Constipation causes fish to float on their sides. Deshelled peas (any variety) contain enough fiber to make them regular again. If your fish hasn't had a bowel movement in the past few days, feed them two to three fresh peas or thawed frozen peas each day. Mash them or let the chunks float to the bottom of the aquarium.^{[8]
X
Research source}
- Avoid canned peas, as they contain sodium and spices that can hurt your fish.
- Soften the peas. You can do this by boiling them on the stovetop in filtered water for one minute. Allow them to cool down after you remove them from the pan. Don't use a microwave, since this can destroy vital nutrients.
- Remove the skin by peeling it off with your fingers. Make sure you wash your hands first!
- Cut the peas into small pieces. First, cut them into halves if they didn't split naturally when you peeled them. Then, cut them into quarters. If your fish is small, cut the pieces even smaller.
If your fish isn't constipated, they might have eaten too much. Overeating can cause a fish's stomach to bloat and force them to float on their sides. If your fish has had a recent bowel movement, don't feed them for three to four days.^{[9]
X
Research source}
3
Research how your fish sleeps. When fish sleep, they stop moving. For example, betta fish and goldfish sleep by resting on the bottom of the tank. Search online and read books about caring for fish to learn about your fish's sleeping habits.^{[10]
X
Research source}
- Search for this information on veterinary websites or at your local vet's office. Visit your public library or pet store for informative books. If you have access to scholarly databases, search for articles in veterinary journals.
- Some fish like to play dead just to see you freak out. Be sure to double-check
4
Condition the aquarium water. Chlorine, chloramine, and heavy metals in tap water can sicken and kill fish. Add water conditioner to the aquarium, following the instructions on the packaging. You can buy water conditioner at your local pet store.
- Test your tank water for chlorine, chloramine, and heavy metal before adding conditioner. You can buy testing kits at your local pet store. Follow the instructions on the package to avoid false positives or negatives.
- Alternatively, you can buy distilled water from your local grocery store and use that in your tank instead of tap water.
5
Check the water temperature. If you recently changed the water, any sudden change in temperature could send your fish into shock. Measure the temperature with an aquarium thermometer. If the temperature is above or below the ideal range recommended for your fish, adjust the thermostat on the aquarium heater.^{[11]
X
Research source}
- Monitor your fish to make sure it returns to normal behavior after the temperature has normalized.
- In the future, stick to regular partial water changes to avoid sudden changes in temperature or pH.
- If you need to change a large amount of water, remove your fish before doing so. Place your fish (and their water) in a plastic bag and then slowly acclimate them to the new temperature by floating the bag in the tank.

Expert Q&A

Search

Add New Question

Question

How do you take care of your goldfish if you still don't have a filter and an oxygen machine? We cant find any if those in our area. The fish have been in a bucket for two days now. Is that okay?

Lauren Baker, DVM, PhD
Veterinarian
Dr. Lauren Baker is a Veterinarian and Assistant Scientist at the University of Wisconsin-Madison. With over 10 years in veterinary medicine, she specializes in the concept of “one health,” which uses insights from veterinary medicine to help human medical research. She holds a Ph.D. in Comparative Biomedical Sciences, a Doctor of Veterinary Medicine, an MS in Comparative Biomedical Sciences, and a Bachelor’s degree in Psychology from the University of Wisconsin-Madison.

Lauren Baker, DVM, PhD

Veterinarian

Expert Answer

This is not okay. Fish need to have the water constantly aerated and filtered as they eliminate waste and deplete the water of dissolved oxygen. You can order what you need from the internet pretty easily. Until then, keep performing partial changes of the water to dilute ammonia levels. The newly added water will also introduce more oxygen to the tank.

Thanks! We're glad this was helpful.
Thank you for your feedback.
If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
Yes No

Not Helpful 20 Helpful 60
Question

My fish looks dead, but he sinks to the bottom and doesn't float up. He also doesn't do anything when you take him out of water. But yesterday he would wiggle when you took him out, now he doesn't. Is he dead?

Lauren Baker, DVM, PhD
Veterinarian
Dr. Lauren Baker is a Veterinarian and Assistant Scientist at the University of Wisconsin-Madison. With over 10 years in veterinary medicine, she specializes in the concept of “one health,” which uses insights from veterinary medicine to help human medical research. She holds a Ph.D. in Comparative Biomedical Sciences, a Doctor of Veterinary Medicine, an MS in Comparative Biomedical Sciences, and a Bachelor’s degree in Psychology from the University of Wisconsin-Madison.

Lauren Baker, DVM, PhD

Veterinarian

Expert Answer

It sounds like he may be dead. If he isn’t, it sounds like he is close to death. You should consider euthanizing him with the clove oil as described in the article. It may be hard, but it's the best thing you can do for your fish.

Thanks! We're glad this was helpful.
Thank you for your feedback.
If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
Yes No

Not Helpful 38 Helpful 95

Ask a Question

200 characters left

Include your email address to get a message when this question is answered.

Submit

Video

Read Video Transcript

Tips

If you notice strange spots or markings on your fish, call your veterinarian. This might be a sign that they have a disease.

Thanks
Helpful 4 Not Helpful 1

Tips from our Readers

The advice in this section is based on the lived experiences of wikiHow readers like you. If you have a helpful tip you’d like to share on wikiHow, please submit it in the field below.

Avoid putting pointy plastic or glass objects in the tank, like plants. These can hurt your fish's fins or tail if they run into them or break.
If your fish is dead, don't leave it in the tank. Leaving it in the tank might spread diseases to your other fish.

Submit a Tip

All tip submissions are carefully reviewed before being published

Name

Please provide your name and last initial

Submit

Thanks for submitting a tip for review!

Warnings

Don't remove your fish from the aquarium unless you're certain that they're dead. Most species can't survive out of water for very long.

Thanks
Helpful 7 Not Helpful 4