kahuna

I have a 55 gal community tank, no aggressive inhabitants.

Use API Test, ammonia @ 0, nitrite @ 0, Nitrates @ 20.

I have purchased 14 corydoras in the last 4 months, punctatus, schwartzi and julii. All were purchased @ various times in groups of at least 3.

All were introduced to the tank in a 45 min period with 3 small amounts of water added to bag.

As of today, I am now down to 2? All have died after a minimum of 2 weeks in tank and never more than one at a time (no mass die-off). No signs of damage or sickness with the exception of 2-julii which exhibited red around the mouth.

I currently have 7 neon tetra which have been in the tank for approx. 2 months, so I would assume they would be the first to go if water conditions were poor, which they are not.

I really want to keep a school of 6 to 9 corydora but need to find out why they keep dying. Is it possible my pH-8.4 is too high for corydoras? All my fish were purchased @ the same LFS and I have not lost a single fish from there. Any help would be greatly appreciated.

ABCDemily

Generally, the ones you have are the less hardy of the cory species, I think the most hardy is the albino.

On the other hand, it may just be that the LFS you buy from has a bad stock.

Or the tank isn't old enough, cories need a very established tank to survive, maybe yours just isn't old enough?

Good luck, I love cories

*EDIT*

Cories don't like nitrates generally of over 10-15, maybe look into lowering those first, that's why I don't keep thenm, my nitrates in tap water are 40!

Shawnie

im sorry for your losses..they are amazing fish for sure... that is a high ph and although ive only had julie's out of your cories, without issues, im not sure even with proper acclimation if that ph might be your issue...im even surprised as you say that your neons are ok...is there a reason you keep it so high?

kahuna

Besides the Albino, can you suggest other cories that are hardy?

Unfortunately my well water has nitrates of 10 so I do weekly 50% water changes. But I guess I may have to give up on the cories.

kahuna

I am on well water and that is the natural ph. I really do not want to get into altering the ph. I guess I might just have to accept the fact that cories are not meant for this tank. Thank you.

bolivianbaby

My daughter keeps peppered corys and hasn't had a problem. Her nitrates stay around 5, though. I have albinos and juliis, but my nitrates stay at 5-10.

Shawnie

im also on well water but I do run a softner and my ph is 7....I dont think having nitrates is an issue tho ....I agree no altering as a stable one is much better....im still shocked with your well that the ph is that high...I wish you luck with all the fish babies!

kahuna

I actually do have a softener and it is still at 8.4, unbelievable huh. Thank you, I guess maybe I will try something more adaptable to my water.

Shawnie

wow that is unbelievable! do you know the expiration of the test kit as someone asked ? check the lot# on all the bottles ...

CHoffman

SO sorry your having problems. I have terriable water to. It ranges between 7.8-8.2 Ph and between 10 and 20 nitrate right out of the tap. It's crazy. I keep peppered cories in my 120gallon. They are sweet little things and seem pretty hardy. I would give them a try. Even when I had a driftwood problem that killed my anglefish the cories lived. They are very sweet little things. Also try the drip method for acclimating. Do it over about 2 hours. I really think this will help. Cories can be sensitive to change so a SLOW acclimation is a great start to getting them used to your water. I'll find a link showing you how to do it.

aquarist48

Hello. So sorry to hear about your fish loss. I have well water and my pH is off the charts it's so high. I have to mix distilled and spring water to get my pH to 8.0. Once I do (my tank is "very" well established) get it to 8.0 I can do my water changes with all well water and the tank doesn't go over 8.5. It just takes some practice to get the level you want to start with. I have a common cory cat and it's about 8 years old. My pH levels mostly stay at 8.0. So I don't know for certain that your pH levels are the problem either.
Here is a link you may find helpful (in case CH doesn't find it)
http://www.fishlore.com/acclimating-tropicalfish.htm

kahuna

Okay, if I understand this correctly the last 4 numbers of the lot# is the expiration? If that is correct than they range from 6/08 to 9/08 which puts all expired. That really stinks because I purchased this @ Petsmart in May of 09.

But I still have approx. 17 other fish along with mega platy fry. The cories are the only fish I have lost. So if the tests were completely wrong I would expect to be losing other fish as well?

Shawnie

no its 3 years from that number according to other members...so I think you are safe....as others have said, it just might not be able to handle the higher end of the ph and going for some less sensitive ones might work ...good luck!

kahuna

Okay, you are now giving me hope. Your water conditions are very similar to mine. I have seen pics of the peppered cory but have never seen them at my lfs, but I believe I may go fish shopping today. I have 2 cories left, a punctatus and schwarzi, they are from the earliest groups I purchased and I would very much like to give them a larger school. Thank you.

kahuna

Thank you, another voice of hope here. My ph never seems to change, it is extremely consistent @ 8.4, so possibly if I try a hardier cory such as the peppered cory I might make this work.

alicem

Hi kahuna,
My water comes out of the tap @ 7.4 and within 4 hours raises to 8.2.
I'm told it has to do with co2 (or lack there of, I've forgotten which) that the water co. adjusts in the water
to keep the pH lower so it doesn't damage thier pipes.

Needless to say, I pre-condition my replacement water for partial water changes.
All my tanks sit at pH 8.1 to 8.2 High? yes, but stable.
I keep both panda and sterbae corydoras.

I did a little research on your cories:
Planetcatfish states your corydoras punctatus does better in a lower pH and is a very social catfish.
It will not only get along with other cats, but will do better with them.
So planetcatfish strongly recommends keeping them in a shoal with any corydoras.

Also, according to planetcatfish the schwartzi species is still imported in large numbers,
so they recommend quarantine, especially if adding to groups in well established tanks.

As a suggestion, if you don't have access to a local breeder, I would try albino, emerald green or bronze corydoras.
They are bred from the same species, lean toward the higher end of pH (7.8-8.0)
and should be adaptable to your pH if you acclimate them carefully.

All cories are sensitive to water conditions at the bottom of the tank, so
gravel vaccing and doing partial water changes low in the water collum might help your cause.

How thick is the gravel in your tank?
2" should be plenty and will hold less debris and make gravel vaccing easer.
If you have alot and want to remove some, post that info and we can help you so you don't have mini cycle problems.

Be sure they get food. They do much better if not treated as scavengers, but are fed like other fish.
You could try adding sinking food after lights out... with the following disclaimer:
Since you have only 2 right now, don't accidentally over do it and pollute the tank.

I hope at least some of this helps you,
alicem

dvc_r

I'm on the same wavelength with CHoffman and Aquarist48. Call up your LFS and ask them what there ph runs. (I always check the water in the bag myself) If there is a large ph difference, that might be the problem. Slow drip the cories for a longer time. Cories can be real sensitive to ph swings. I don't think the nitrates would be a factor because they have the ability to swim to the top to get air when water chemistry is not perfect. Although if they are constantly going to the top for air- that would be a red flag.

snowflake311

Omg I can't keep cory cats too. I also have lost 14 cory all seem to only live 1-2 weeks. I thought it was due to the bad batch at the store.

My tank is 55 gal planted sand ammonia 0 nitrites 0 nitrates 10 ph 6.5 I have soft water. I talked with another person on a site. I think there might be something in my water that effects the cory something I can not detect maybe copper zinc something. I bought 3 schwartz and only have one left it's been 2 weeks.

I'm trying to find other fish keeperss in my town and see if anyone has had the same problem. Because like you I keep up with
MY water changes and sand cleaning. It just does not make sence that I can't keep them but can keep rams medusa pleco and spawn blue acaras.

So I feel your pain.