Keeping corydoras????

[ginty]

Have all of your cories come from the same place? There have been several stores in my history of fish keeping I have learned to just avoid because everything I ever got from there died within a matter of months. I found one individual store where nothing I purchased from there ever lasted longer then about 3ish months. Sometimes, the issue can be the supply rather than your tank. Just an option worth looking at. At a glance, your tank seems fine. I agree that most regularly available cories shouldn't have an issue adapting to your pH. It is a tad high, but I doubt that is your issue here.

Yes i got them from pets at home. I suppose it could be that they have a problem there??
I hope so because i would hate to be the cause of there death

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[trennamw]

If they last a week after getting to you it's probably not the store.

We all hate to think it's something we are doing ... But at least then it'd be something solvable.

We really shouldn't be commenting that the water is fine without knowing how often you do a water change, and how much. Without that info I'm inclined to think it's water quality. I keep reading cory keepers say, it's not rough but dirty substrate that hurts them.


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[absolutangel04]

I don't think your substrate is killing them. That is mostly a myth. Yes, you can have issues in some circumstances with too much bacteria built up in your substrate (be it sand OR gravel). No part of this looks like substrate death IMO. The deformation and rising to the top are indicative of a much greater issue than some barbel wear. It can indeed potentially be a bacterial infection. But, since it took the cories that quickly, I would be inclined to think that it is something they came in with. Stuff like that has the potential to pass to other fish, but of course that depends on a variety of other factors including the strength of the immune system of your other fish.

For what it is worth, when you get bad stock, the time line for their demise is generally in the span of about 3ish months after you get them. It is not necessarily instantaneous. Death a week after purchase in a clean tank with solid parameters usually screams "bad stock" to me.

Asking your water change schedule is certainly a valid point. IME, usually people have a pretty decent pwc schedule though to maintain parameters like the ones mentioned. If not enough water is being changed, the parameters typically reflect it and the nitrates stay up at more like 40ppm. Though, asking the specifics is never a bad thing either.

At the end of the day, you do the best you can, and sometimes fish die and then you feel bad. Since you have had so many deaths, I would always suggest doing one or more very large pwc ( can be on consecutive days) with a very thorough gravel vac to try and make sure anything icky that may have gotten into your water has been removed. If you want to try cories again, I would try a different store. If you are concerned about your gravel harboring too much gunk, then vacuum the crap out of it (figuratively and literally). If you are concerned and would rather not try cories again right now, then do what you are comfortable with. Personally, I like gravel. But, if you want sand, look into play sand or some other cheap option. It is way cheaper than gravel. Pet store sand is quite pricey, but there are other options.
Also, if you have a tank that can be set up as a quarantine tank, that would be most helpful.

 

[trennamw]

Whether nitrates at 25ppm indicates good tank hygiene would be easier to judge if we knew beginning and end readings over a week.

When I follow 50% weekly water changes I have almost zero nitrates. And I believe I start seeing fish health issues when they're above 20 for very long. It's also very hard to tell on the API color chart whether it's 20 or 40.

So I still suspect water changes are an issue.


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[ginty]

Whether nitrates at 25ppm indicates good tank hygiene would be easier to judge if we knew beginning and end readings over a week.

When I follow 50% weekly water changes I have almost zero nitrates. And I believe I start seeing fish health issues when they're above 20 for very long. It's also very hard to tell on the API color chart whether it's 20 or 40.

So I still suspect water changes are an issue.


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I used the liquid api colour chart and i used a paper strip test to double check it and thats what my nitrates were.

My tap water is 30 for nitrate. And thats the same around the area i live. Im currwntly in the process of getting more plants. But my nitrates isnt the issue i dont think.
Ive found out the platty that dyed was inter bred, and the corys got ill due to my rough gravel. It damaged their barbels. I was given the wrong advice about the corys and im devastated about it. I will not get them again unless i get the right substrate.

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[ginty]

I do water changes every saturday. 50%. And during this change i vacum the gravel.

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[RightTurnClyde]

Best of luck to you. I have problems keeping Corys alive too even though all my other fish are fine. My PH is around 8.0 out of the tap as well. I've since added some driftwood which brings it down to about 7.8 due to the tannins that are gradually released. I think they just don't like the high PH, hard water. Although, I believe the Peppered Corys are supposed to be one of the hardiest species. My last Julii Cory died a couple weeks ago. I'm going to try a different species soon, but if those end up dying too, I think I might give up on keeping Corys.