Julii cory died within two days

[Grimhowl]

Hi guys I'm new to the forums here. I had some casualties this week and I'm trying to figure things out

I purchased two of these little Julii cory cats from Petco the other day (they were fairly small, maybe half an inch) and they both died already! My aquarium is well established with no nitrates/nitrite and hardly any ammonia at all if any. PH of around 7 I think but I would have to double-check that. I do weekly water changes and gravel vacs. It's fully planted and my other fish have all been happy and healthy for the two years I've had them. I wanted to get my albino cory cat some pals and figured my tank would have no problem with the addition but that wasn't the case.

As for the deaths, one had large red spots on his sides that I assume is the red blotch disease. I don't think this came from my tank as none of my other fish have ever had problems (I also dose medications into my tank every three weeks). This is the first fish I've introduced outside of my initial tropical team which includes 3 glowlight tetra, 3 neon tetra, two large female platties, a nerite, and my one cory cat. The second death was somewhat of a mystery. The cory would swim to the surface and then list down on its side as if being deprived of oxygen. With all the plants I have and the surface agitation I can't see how that would be an issue. My gravel is smooth volcanic ash with no sharp edges. Basic plant decor with driftwood.

The second cory I had taken out of my tank and placed in a hospital area with pristine water and his breathing slowed and he eventually just stopped. His fins were twitching as well I assume from his brain shutting down? But, otherwise no visible anomalies like the first. I really want to get some more bottom dwellers for my ten gallon but I'm afraid to buy more despite having a presumably healthy tank. My albino cory has never had any issues so how could it be that my two new additions died so suddenly. Could it really be a problem with my tank's health?

 

[itiwhetu]

What medications are you using and why?

 

[AdoraBelle Dearheart]

Can you post your water test results please? What testing product do you use to test for ammonia/nitrites/nitrates?
In a cycled tank, you should have zero ammonia, and there should be some nitrates... what kind of filter do you have and had you changed or cleaned it recently?

Do you use a gravel vac?
Do you do water changes? How often and how much of the volume of water do you change?

Your stocking is a bit off I'm afraid, you have a lot of different schooling species that don't have large enough schools, but wouldn't have space in a ten gallon to have proper schooling sizes for those fish either, sadly. I'm sorry to be the bearer of bad news! It's really common as a beginner to want to 'pick and mix' and have a few of each fish, but that can lead to other issues down the road, and schooling fish really do need a minimum of six of their own species. There's a lot you can do with a ten gallon, your current stocking isn't really ideal though... we can give further advice on that!

I suspect that either you'd cleaned or changed the filter, the fish were already sick from the store, or the added bioload was just too much for your tank, and it caused an ammonia spike. The red marks on the belly are typical of an ammonia/nitrite spike death.

If you'd like more bottom dwellers, and your albino cory would certainly be much happier with some other cories - is there any chance of you upgrading to larger tank? That would allow you to increase the schooling sizes for the fish you currently have.

 

[Colin_T]

Can we get some pictures of all the fish, and a picture of the tank?

I don't think this came from my tank as none of my other fish have ever had problems (I also dose medications into my tank every three weeks).

You don't want to add medications unless the fish are sick. All fish medications do harm to the fish. Fish can also become addicted to medications and their immune systems stop working. Then if you stop adding chemicals they die from withdrawal or diseases.

Continuous dosing of chemicals can also lead to drug resistant diseases that can't be treated.

Medications should only be used if the fish have a known disease.

Fish live long healthy lives in clean water without chemicals, don't add things unnecessarily.

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What are the ammonia, nitrite, nitrate levels in numbers?
Ammonia and nitrite should always be on 0ppm, and nitrate should be less than 20ppm.

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The red spot/patch on one Corydoras might have been a bacterial infection or a wound where it got spiked by the other fish in the bag.

The second Cory that died sounds like it could have been poisoned.

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Stop adding chemicals.

Do a 75% water change and gravel clean the substrate every day for a week.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.

Don't add any new fish for a month. Monitor the remaining fishes and post pictures if any look or act unusually. If everyone is fine in a month, maybe add some more fish. Try to quarantine new fish for a few weeks before adding them to an established display tank.