Guppy struggling to swim

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Apr 7, 2024
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Hi, this is my first time posting and I have no idea what to do. I’ve only owned my guppies for three months so I’m quite new to fish keeping.

I found my smallest guppy (Canyon) struggling to swim this morning. I found him struggling near the bottom but when I came near, he was twirling upwards. I have no idea what’s caused this, my other 5 guppies are fine. He is gasping for air so I’ve set up a little container while I rush to get a little floating container with holes from my local store.

I had an issue with one guppy who had his tail a bit bitten so to prevent fin rot/make sure it wasn’t, I did a treatment of Waterlife fin rot and ulcers that has Myxazin in. I had it on had so I thought it would be fine. The treatment ended 4 days before this.

I have done a water change and added the oxygen pump to the water. The only reason I don’t have it all the time is because at the moment I only have plugs for the heater, light and pump.

My tank is 54L, I have 6 guppies all together and a few shrimp. The temperature is 25.3, pH is at 8 (normally it’s 7.4-7.8), nitrite 0ppm and ammonia looked between 0-0.25ppm. Lastly, I spilt one test tube that I did before I performed a water change so I used a test strip for the nitrate which was 0ppm. They got this new upgrade a few weeks ago and have been fine. Today was supposed to be water change day which I do weekly.


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Video of the fish?
upload videos to YouTube then copy & paste the link here.
if you use a mobile phone to film the fish, hold the phone horizontally (landscape mode) so the footage fills the entire screen.
Video of the fish?
upload videos to YouTube then copy & paste the link here.
if you use a mobile phone to film the fish, hold the phone horizontally (landscape mode) so the footage fills the entire screen.

Here’s the link. I hope the quality is good enough. Thank you so much for the reply!

I do have the water in the floating tank shallower as he’s struggling so much but for the video, I thought it best to be deeper.

This is a vertical video of him released in the tank before I put him back. I filmed this before I read horizontally but I didn’t want to stress him out by doing it again
Could be swimbladder problem.
It's most likely a swim bladder problem and Myxazin didn't do anything to help so it's not an infection that responds to that treatment.
There's no cure for swim bladder problems regardless of what pet shops say so euthanise the fish.
A little update. I can see this white cloudy stuff near his mouth. Could this be cotton wool disease on the mouth instead?


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Hard to say but looks more like fungus than Columnaris. Try adding salt if you want to try and treat that but the underlying issue (swim bladder issue) remains and won't get better.

The fluffy mouth and swimming problems have nothing to do with each other and are separate issues.


You can add rock salt (often sold as aquarium salt), swimming pool salt, or any non iodised salt (sodium chloride) to the aquarium at the dose rate of 1 heaped tablespoon per 20 litres (5 gallons) of water. If there is no improvement after 48 hours you can double that dose rate so there is 2 heaped tablespoons of salt per 20 litres.

If you only have livebearers (guppies, platies, swordtails, mollies), goldfish or rainbowfish in the tank you can double that dose rate, so you would add 2 heaped tablespoons per 20 litres and if there is no improvement after 48 hours, then increase it so there is a total of 4 heaped tablespoons of salt per 20 litres.

Keep the salt level like this for at least 2 weeks but no longer than 4 weeks otherwise kidney damage can occur. Kidney damage is more likely to occur in fish from soft water (tetras, Corydoras, angelfish, Bettas & gouramis, loaches) that are exposed to high levels of salt for an extended period of time, and is not an issue with livebearers, rainbowfish or other salt tolerant species.

The salt will not affect the beneficial filter bacteria but the higher dose rate (4 heaped tablespoons per 20 litres) will affect some plants and some snails. The lower dose rate (1-2 heaped tablespoons per 20 litres) will not affect fish, plants, shrimp or snails.

After you use salt and the fish have recovered, you do a 10% water change each day for a week using only fresh water that has been dechlorinated. Then do a 20% water change each day for a week. Then you can do bigger water changes after that. This dilutes the salt out of the tank slowly so it doesn't harm the fish.

If you do water changes while using salt, you need to treat the new water with salt before adding it to the tank. This will keep the salt level stable in the tank and minimise stress on the fish.

When you first add salt, add the salt to a small bucket of tank water and dissolve the salt. Then slowly pour the salt water into the tank near the filter outlet. Add the salt over a couple of minutes.

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