Cories Dying, Just Added River Rock

[jessiepbg]

I'm new to Cories, I just got 6 at the beginning of the month, 2 peppered, 2 julii, and 2 panda, as tank mates for my Betta in a 10 gallon tank. The Betta doesn't bother them and the tank parameters are: Ammonia - 0ppm, Nitrite - 0ppm, Nitrate - 5ppm. It finished cycling this sunday and I cycled with the cories and the betta in the tank with lots of water changes and no signs of discomfort. I added river rocks yesterday morning and think I forgot to boil them before adding them. Everyone seemed to be doing alright with them. I woke up this morning and the panda cory that had never really acted right was dead, and the rest of the cories were very lethargic. The Betta seemed unfazed, but I pulled him out of there anyway. The cories are in a 1 gallon qt tank, but I didn't have any water prepared but what was already in the tank, so they're in that until I can get some more water heated up for them. Does anyone have any suggestions on what I can do to save my remaining 5?

[PanzerFodder]

I would think that you should take the rocks out and do a major water change, it maybe that the rocks have changed your PH in some way or maybe there was some polution in the river that they came from?.

Check your PH to see if it has changed in some way.

[MatsP]

What is the pH and temperature of the tank? Are you sure the nitrite and ammonia are both zero?

--
Mats

[jessiepbg]

I took the rocks out, boiled them, and did a 100% water change. The pH might have changed, I think my water generally sat at 8.4, but I just did a check and it was at 8.0. I'm not used to keeping track of the pH, since Bettas just adapt to whatever you throw them in. Is there something I can do to adjust it for the cories? The rocks were from Hobby Lobby, so I have no idea exactly where they were picked up from. I'm leaving the cories in their 1 gallon tank with no substrate and a hornwort plant until I get off work. They look like they're feeling better in there than they were in the big tank. I'm just going to have to see how they're doing tonight.

The temp is around 76 F btw.

[MatsP]

Assuming your fish came from tanks in your LFS that also has tap-water like yours, I don't think you should worry about the pH. pH is by far the hardest part to change in water (at least in a way that actually makes the fish feel happier). And clearly the pH is not wrong in your tap-water, or your 1g tank would have the same problem.

I suspect you have nitrite or ammonia in the water. This is HIGHLY toxic, and definitely kills fish.

--
Mats

[jessiepbg]

I'm very sure I don't have high levels of ammonia or nitrite in my big tank or QT tank. I've tested with both my API liquid test and a strip test, the API test having been very accurate for me over the last few weeks while I've cycled my tank. I use Prime as a water conditioner to remove the small amount (less than .25ppm) of ammonia that is present in my untreated tap water. The first thing I did when I saw the cories having trouble was run tests for ammonia, nitrite, and nitrate. My betta is very sensitive to ammonia and nitrite changes as well and is still in my 10 gallon tank with no obvious signs of distress.

Do you have any other suggestions for me? They're in the 1 gallon tank half-full and with a big hornwort plant in there for cover and they still don't look like they're feeling any better. All the water in the tank currently is fresh out of the tap, conditioned, and warmed up to 76 degrees. I just did a water change, so there shouldn't be any ammonia or nitrite in there even though they've been in it for a few hours.

[PanzerFodder]

Over feeding maybe? I just thought that I would mention that because that is what I did when we were first given or 10G tank, all the fish looked sick and all of my daughters swordtails died plus her guppy.
After I did a large WC and then some 10% one's each day things soon got back to normal.

I would try to reintroduce a couple of fish at a time to see how they get on in the fresh water.

You have to be very careful with the smaller tanks as the volume of water is small and you have a lot less margin for error than with one of the bigger tanks.

Cheer's...PanzerFodder...

[Firestorming]

When a good friend of mine had an lfs he often had folks come in with fish that had "just" died. After a while we found a pattern of people using rocks they collected locally, turns out the local council was doing herbicide and pesticide spraying. Is it possible that the rocks you have might have been subjected to any toxic sprays?

I also helped another mate clean his koi pond after a neighbour had a pest guy spray her backyard for spiders, the wind carried some mist off the spray onto his ponds. Resulted in $25K worth of dead show koi.

[jessiepbg]

Thanks for the reintroduction idea, I've been dreading putting these guys back in that tank. I think I'll leave that for the morning though. They're starting to work their way up into the hornwort, which I'm hoping is a good sign. The panda was pointed into a corner and just sort of shaking though. He might have been trying to swim into it, but I really couldn't tell. He stopped and swam away when I moved the plant.

I bought the rocks at Hobby Lobby, so I have no idea where they came from originally. I was an idiot and forgot to boil them when I first put them in. I boiled them today and put them back in with the Betta and he isn't showing any signs of distress.

Wow, that's a shame about those koi. It's scary how many variables there are in keeping fish.