My new koi's eyes got cloudy over night

[QSmith491]

I've already looked online about the possible illnesses linked with this. But while trying to diagnose my koi, I wondered if the time it took for its eyes to become cloudy could help. Last night, the koi's eyes looked absolutely fine. This morning, both eyes looked very cloudy and bulbous.

In addition to this, the koi is very new. I got it only 3 days ago. All of my other fish are completely fine, so it seems unlikely that it could be the water quality. However, I do still plan on checking the water as soon as possible. And aside from looking like it can't really see, the koi seems fine. It swims around and eats as much as my other fish.

Since I had to go to school, there wasn't much I could do before leaving, but I did put it in a sort of quarantine tank I had set up. It's full of random snails I just didn't want to kill. I did a very large water change in it a day or two ago, so I figured it would have better water quality if that was indeed the issue. Plus, if it were parasites, my other fish are at less risk.

 

[Demeter]

Usually if both eyes are cloudy it is a result of bad water quality. Are you familiar with the aquarium nitrogen cycle? Can you test for ammonia, nitrite and nitrate? Parasites are unlikely as they rarely effect the eyes. A bacterial infection may be set in due to the stress of being new and possibly bad water.

Koi are large carp that almost always require a big pond as they grow. I hope you have a large (hundreds of gallons) tank/pool/pond you can house them on when they are older.

 

[BillbertBuzzums]

I've already looked online about the possible illnesses linked with this. But while trying to diagnose my koi, I wondered if the time it took for its eyes to become cloudy could help. Last night, the koi's eyes looked absolutely fine. This morning, both eyes looked very cloudy and bulbous.

In addition to this, the koi is very new. I got it only 3 days ago. All of my other fish are completely fine, so it seems unlikely that it could be the water quality. However, I do still plan on checking the water as soon as possible. And aside from looking like it can't really see, the koi seems fine. It swims around and eats as much as my other fish.

Since I had to go to school, there wasn't much I could do before leaving, but I did put it in a sort of quarantine tank I had set up. It's full of random snails I just didn't want to kill. I did a very large water change in it a day or two ago, so I figured it would have better water quality if that was indeed the issue. Plus, if it were parasites, my other fish are at less risk.View attachment 634152View attachment 634153

What size is your tank?

 

[QSmith491]

What size is your tank?

It's 55 gallons. I have a pond though that I could've put the koi in when it got too big. But the koi is dead already.

 

[QSmith491]

Usually if both eyes are cloudy it is a result of bad water quality. Are you familiar with the aquarium nitrogen cycle? Can you test for ammonia, nitrite and nitrate? Parasites are unlikely as they rarely effect the eyes. A bacterial infection may be set in due to the stress of being new and possibly bad water.

Koi are large carp that almost always require a big pond as they grow. I hope you have a large (hundreds of gallons) tank/pool/pond you can house them on when they are older.

I tested the water, it was a little high in a ammonia and nitrates. But again, none of my other fish have been affected. I treated it for a bacterial infection but the koi still died. Thank you for your help anyway though.

 

[Demeter]

Sorry it was too late. It was likely the ammonia amd the stress of being a new fish. Some fish are more sensitive than others, stressed fish, younger ones and already ill ones are more likely to be effected by ammonia amd high nitrate.

In a healthy tank there should be no ammonia or nitrite present. Either your bioload is too high for the tank to process or the tank wasn’t cycled in the first place. Nitrates are not usually a huge problem but they can cause issues over time when they get too high, which is where frequent water changes come in.