Pygmy Cories Keep dying!

[fishdogs]

I am on my SECOND batch of Pygmy corydoras in a month. The first round (6 of them) introduced ich to my 20H tank. After treating, 4 of them died (it sounds like the medication Ich X is really bad for cories?). I recently went to get 6 more Cories two weeks after ich was eradicated for a total of 8 in my 20H with 3 mollies. The mollies have not been aggressive at all towards the Cories. 
 

Each batch of fish are from a different reliable aquatic store. 
 

Current water parameters:

GH: 0 (trying to fix with seachem equilibrium)

NO3: 0-10 (apparently ANY ammonia AT ALL is lethal to pygmies?)

NO2: 0

Cl2: 0

KH: 0 

pH: 6.4-6.8

Temp: 76*

 

Edited March 26 by fishdogs

[Colu]

Ick X is effective at treating ich and shouldn't be harmful to your Cory's I would also want to add a small amount of aquarium salt 1 table spoon for 10 gallons as ich causes massive electrolyte lose salt will add back in essential electrolytes  you want zero ammonia and nitrites if you detect any ammonia or nitrite do a large water change and add a double dose of prime to help detoxify any ammonia or nitrite test daily till your ammonia or nitrite constantly stays at zero is there something going on with your second batch of pygmy Cory's I would just add some crushed coral to your substrate to gradually raise your KH and GH you will need to add 1 pound of crushed coral per 10 gallons @fishdogs

[anewbie]

On 3/26/2024 at 6:03 PM, fishdogs said:

I am on my SECOND batch of Pygmy corydoras in a month. The first round (6 of them) introduced ich to my 20H tank. After treating, 4 of them died (it sounds like the medication Ich X is really bad for cories?). I recently went to get 6 more Cories two weeks after ich was eradicated for a total of 8 in my 20H with 3 mollies. The mollies have not been aggressive at all towards the Cories. 
 

Each batch of fish are from a different reliable aquatic store. 
 

Current water parameters:

GH: 0 (trying to fix with seachem equilibrium)

NO3: 0-10 (apparently ANY ammonia AT ALL is lethal to pygmies?)

NO2: 0

Cl2: 0

KH: 0 

pH: 6.4-6.8

Temp: 76*

 

It is unusual for tap water to have 0 gh; do you know the tds or ec? This water would not be suitable for molly if the parameters are correct but of course very good for the pygmy. As to the death - how long has the aquarium been running; a mature aquarium should have 0 ammonia and very small amount of ammonia can be deadly to many species of fishes but yes the tiny pygmy are going to be more sensitive to it. However acidic water will reduce the impact of ammonia. You can add a few drops of something like prime to help neutralize the impact of traces of ammonia but the bigger question is why does the aquairum have ammonia in the first case. Pygmy are definitely a more 'fragile' species though once established they are  hardy. I would not add salt to the aquarium esp if you plan on growing live plants. Having said that the molly will jump for joy with you add a bit of salt.

[fishdogs]

I did forget to mention that I use RO water as the tap water here is a little sketchy. 
 

My tank has been running for about a year and the mollies have been in it the whole time thriving. 
I do have a small anubias nana and some floating frog-bit hoping that would help with some ammonia/nitrate levels but I’m still not sure why the levels are higher.

[Colu]

On 3/27/2024 at 10:37 AM, fishdogs said:

I did forget to mention that I use RO water as the tap water here is a little sketchy. 
 

My tank has been running for about a year and the mollies have been in it the whole time thriving. 
I do have a small anubias nana and some floating frog-bit hoping that would help with some ammonia/nitrate levels but I’m still not sure why the levels are higher.

You if your using pure RO and not remineralizing that will be a problem for your mollies need  a minimum kH 180ppm minimum GH 200ppm pH 7.5-8 long term to thrive low KH and GH can cause bent spine due to mineral deficiency hole host of other health issues I would start to remineralizing your RO water 

[fishdogs]

I have been using seachem equilibrium to try and help the GH. There are some mixed reviews on whether or not KH is important which I feel like it is. I really don’t want to spend another $100 to have more solutions to add to the tank everytime I change the water. Is there any specific remineralizing agents that work best for RO water?

[Colu]

I don't use remineralizers am going to tag @Mmiller2001he has more experience then me when it comes to remineralizing RO water 

Edited March 29 by Colu

[anewbie]

On 3/27/2024 at 7:05 AM, fishdogs said:

I have been using seachem equilibrium to try and help the GH. There are some mixed reviews on whether or not KH is important which I feel like it is. I really don’t want to spend another $100 to have more solutions to add to the tank everytime I change the water. Is there any specific remineralizing agents that work best for RO water?

For the pygmy I'd try a drip acclimination. Basically take a 5 galllon (or even 1 gallon) pail which has never been used for cleaning; put the pygmy in there with their water and then slowly drip water via an air-tube hose with a knot into the pail - I'd do that for an hour or so at 1/2 gallon per hour drip rate (the numbers don't have to be exact). RO water is closer to their native environment than hard-water. You are at a cross here because if you make the water super hard like 180 ppm the pygmy won't like that much; so you will have to compromise. I'd suggest something closer to 60-80 which is more favorable to the pygmy. KH isn't super important but the molly will want some calcium. Also if you add kh the ph will rise and that will impact the cycle and bacteria in the aquarium.

[Mmiller2001]

I would buy MgSO4 (Epson salt) CaSO4 and K2CO3. All are inexpensive and will last a year or more. Ca and Mg for GH and the K2CO3 for KH if you want to add it. I personally don’t add KH to my RO water but some African species of fish will need it.

Edited March 28 by Mmiller2001