Mysterious Pygmy Corydoras death?

[lynxfishy]

Hello everyone, I am fairly new to the fish keeping hobby and earlier in the year I set up a 10 gallon planted tank. I let it cycle for a month and begin adding fish in different waves--adding some fish, then waiting a couple weeks before adding more fish. After a couple months of slowly adding fish and testing the water to make sure there was no ammonia spikes I finally have all of my stocking. I currently have a dwarf powder blue gourami, 7 neon tetras (got an extra one from the store thinking they wouldn't all make it back/through quarantine, I was wrong lol), and 5 pygmy corydoras. I recently lost a pymgy cory, and I am really unsure as of why. The water tested fine, no ammonia or nitrite, I have a sponge filter along with a regular HOB filter so the water should have enough oxygen, and I didn't see anything particularly weird about the dead pygmy. All of my other fish are healthy/acting normal. There was some red on the dead pygmy's underside though? But by the time I found him my dwarf gourami could have nipped at the corpse? He has never been aggressive to the other fish, but he does love eating. Any help on the topic would be greatly appreciated. I've attached a current picture of my tank incase it would be helpful. 

[dan12boy]

On 7/21/2022 at 12:24 PM, lynxfishy said:

Hello everyone, I am fairly new to the fish keeping hobby and earlier in the year I set up a 10 gallon planted tank. I let it cycle for a month and begin adding fish in different waves--adding some fish, then waiting a couple weeks before adding more fish. After a couple months of slowly adding fish and testing the water to make sure there was no ammonia spikes I finally have all of my stocking. I currently have a dwarf powder blue gourami, 7 neon tetras (got an extra one from the store thinking they wouldn't all make it back/through quarantine, I was wrong lol), and 5 pygmy corydoras. I recently lost a pymgy cory, and I am really unsure as of why. The water tested fine, no ammonia or nitrite, I have a sponge filter along with a regular HOB filter so the water should have enough oxygen, and I didn't see anything particularly weird about the dead pygmy. All of my other fish are healthy/acting normal. There was some red on the dead pygmy's underside though? But by the time I found him my dwarf gourami could have nipped at the corpse? He has never been aggressive to the other fish, but he does love eating. Any help on the topic would be greatly appreciated. I've attached a current picture of my tank incase it would be helpful. 

I’ve experienced this too. A lot of my Pygmy cories have died unexpectedly but I’m guessing it could be because of the school size, maybe they’re not comfy enough? I really have no idea but I’m going to be adding 15-20 to my 75 and I’ll see from there if they still die unexpectedly. One of them died with its fins slowly deteriorating which I’m guessing was fin rot but I couldn’t setup a quarantine tank and also couldn’t medicate the whole tank. So I just kept the water clean with water changes and it actually stayed alive and thriving for about 2 months before it passed away. 

[David W]

First, your tank is beautiful.

Fish are like any other animal. They can get sick and die, even if we do everything right. They may not show any of the normal symptoms, and still get a viral infection, Bacterial infection, parasites, old age, or even cancer. It just happens some time. It's part of fish keeping and can be extra hard on new fish keepers. 

It looks like you have checked all the important stuff. Maybe check your temp and see if it is where it should be for all of you fish. I will often double check my tanks with a different thermometer.

If everyone else looks fine, I would just keep enjoying your tank and keep a look out for typical symptoms before getting into making any changes or medicating. The best thing to do is to keep up with your routine feeding and water changes. Keep it simple and don't add extra variables.

[Vince C]

I agree with @David W - sometimes we just lose some. I have had a couple pygmy corys not make it, and everything else was stable - and continued to be afterwards. Just keep an eye on things for other issues, and if nothing pops up - don't stress.

 

[nabokovfan87]

On 7/21/2022 at 9:24 AM, lynxfishy said:

Hello everyone, I am fairly new to the fish keeping hobby and earlier in the year I set up a 10 gallon planted tank. I let it cycle for a month and begin adding fish in different waves--adding some fish, then waiting a couple weeks before adding more fish. After a couple months of slowly adding fish and testing the water to make sure there was no ammonia spikes I finally have all of my stocking. I currently have a dwarf powder blue gourami, 7 neon tetras (got an extra one from the store thinking they wouldn't all make it back/through quarantine, I was wrong lol), and 5 pygmy corydoras. I recently lost a pymgy cory, and I am really unsure as of why. The water tested fine, no ammonia or nitrite, I have a sponge filter along with a regular HOB filter so the water should have enough oxygen, and I didn't see anything particularly weird about the dead pygmy. All of my other fish are healthy/acting normal. There was some red on the dead pygmy's underside though? But by the time I found him my dwarf gourami could have nipped at the corpse? He has never been aggressive to the other fish, but he does love eating. Any help on the topic would be greatly appreciated. I've attached a current picture of my tank incase it would be helpful. 

How long have the fish been in the tank?  This might be an acclimation thing and just a sick, stressed fish that took some time to pass in the new environment.  This is typically caused by where the fish came from and having issues prior to your care.

Redness on the bottom of the corydoras usually indicates for me that they want more oxygenation or flow in some way.  Salt would also help if this happens in future to help them perk up a bit when you see that.  It will potentially harm the plants, so keep that in mind.

OK, so.... the biggest thing I can give you for advice right now is that the one big thing you're missing here is testing.  You had a fish pass,  The first thing you'd want to do is to test, report out everything you're seeing for readings, including temperature.
 

 

I would clean out the HoB filter you have as well as the pump / impeller to make sure you're getting the highest flow possible. If that intake sponge is too fine, it could choke out the flow on that filter.  Something to note.