Disappearing Pygmy Corys

[Gabs19]

So we had 3 Pygmy corys in our tank for about 10 months and few weeks ago we realized we couldn’t find 2 of them anymore. We have a 10 gallon tank and we examined every nook and cranny and they’re just gone. We figured maybe they got old and died. We bought a few more 2 weeks ago and the same thing happened! Only one is left. Water parameters are fine and everybody else in the tank is doing fine and behaving normally. Any theories? Is it possible they’re getting eaten? We have 8 tetras (glow light and cardinal), a clown pleco, a kuhli loach, and several mystery snails. 

[Rita]

I am no expert here... but my luck with corydoras is unfortunately about 50% loss, even after quarantine and transferring to the display tank I end up loosing one or two. I suspect yours have died and have been eaten by the pleco and/or mystery snail. I love Cory's and I've resorted to over buying with anticipation of losing about half.

[nabokovfan87]

Please list out everything you can test for, Temperature, and let's talk through your tank setup.

PH and Temp are often the triggers for jumping.  Please check the sides and back of the tank, under the stand, etc and see if they happened to get out that way.

Secondly, I would remove all hardscape, artificial decor, and then go ahead and check substrate. Sometimes you'll siphon up a chunk of something and not realize what it was. It happens, especially on large tanks, unfortunately.

Once we understand what things look like, then we can try to figure stuff out and explain potential solutions.

On 11/21/2022 at 9:41 PM, Rita said:

I am no expert here... but my luck with corydoras is unfortunately about 50% loss, even after quarantine and transferring to the display tank I end up loosing one or two. I suspect yours have died and have been eaten by the pleco and/or mystery snail. I love Cory's and I've resorted to over buying with anticipation of losing about half.

If there's any way I can help please let me know.

[Rita]

On 11/21/2022 at 10:21 PM, nabokovfan87 said:

If there's any way I can help please let me know.

Thanks! But I'm not sure what else I can do... short of using RODI water and veeeerrryyy slowly water changing out to my tap I have no clue how to lessen my losses. No offense to my fish whom I care for dearly, but I do not have the time or patience for RO water... so the best I can do right now is drip acclimate and hope for the best.

Edited November 22, 2022 by Rita
Proof read too late

[Gabs19]

On 11/21/2022 at 10:21 PM, nabokovfan87 said:

Please list out everything you can test for, Temperature, and let's talk through your tank setup.

PH and Temp are often the triggers for jumping.  Please check the sides and back of the tank, under the stand, etc and see if they happened to get out that way.

Secondly, I would remove all hardscape, artificial decor, and then go ahead and check substrate. Sometimes you'll siphon up a chunk of something and not realize what it was. It happens, especially on large tanks, unfortunately.

Once we understand what things look like, then we can try to figure stuff out and explain potential solutions.

If there's any way I can help please let me know.

Nitrate- 10

nitrite- 0

hardness- 300

buffer- 40

ph- 6.8

ammonia- 0

temperature is 80

Unfortunately I don’t have a test kit, only strips. I have tried so hard to raise the ph naturally but it’s always been low. I’ve checked around the tank and don’t see any jumpers. I’ve attached a photo of the tank.

 

[nabokovfan87]

On 11/21/2022 at 10:51 PM, Gabs19 said:

temperature is 80

That's likely the cause.

Let me grab some details and pull up some stuff on the laptop.

Edit:  Here's the details. I am not specific which ones you have.
https://www.planetcatfish.com/common/species.php?species_id=283

Temp listed is 71.6-78.8°F.  I would shoot for 74 degrees for them. 78 is on the high side, but tolerable. Usually this typically means just a shortened lifespan.

For reference, here is another article about the species in question. Good resource for information and setup if you have any concerns.  I think the tank looks great.
https://www.tfhmagazine.com/articles/freshwater/corydoras-in-miniature-full-article

Depending on what other species are in the tank that would determine ideal temp.

On 11/21/2022 at 10:51 PM, Gabs19 said:

Unfortunately I don’t have a test kit, only strips

Those are perfect!

Edited November 22, 2022 by nabokovfan87

[Theplatymaster]

death of depression? I know pygmy cories like big groups. 3 might not be enough

[NOLANANO]

On 11/21/2022 at 10:58 PM, Gabs19 said:

So we had 3 Pygmy corys in our tank for about 10 months and few weeks ago we realized we couldn’t find 2 of them anymore. We have a 10 gallon tank and we examined every nook and cranny and they’re just gone. We figured maybe they got old and died. We bought a few more 2 weeks ago and the same thing happened! Only one is left. Water parameters are fine and everybody else in the tank is doing fine and behaving normally. Any theories? Is it possible they’re getting eaten? We have 8 tetras (glow light and cardinal), a clown pleco, a kuhli loach, and several mystery snails. 

I have had similar experience with Pygmy Cories and Panda Cories. It seems like acclimating to a new tank is tough for them and you lose a decent number each time. Once they get past that initial shock, they live long happy lives though.