Corydoras semi emergency.

I did something to my 29 corydoras tank. I tidied up and moved a couple smooth pebble type stones and I suspect my Corydoras had to squeeze himself out of a tight place. He's pink on both widest parts of his body, belly a little pinkish and some navigation issues. Balance is off. I would only think injury if I hadn't removed mollies from this tank a month or 2 ago with balance issues on male and baby. Mama Molly is still elsewhere and fine.

Tank was unheated when it got cold last week, probably dropped to 66. That's what house dropped to. Yesterday ph about 7.8, nitrates 40 ppm, I didn't want to do water change because of ph, but I did 50%. I have oak trees, I have peat pots. Peat will rapidly drop my ph. I added about 1.5 teaspoons free running salt to.the tank, injured Cory is eating

77 views and no guesses? I'm pulling out more rock so I can get a good look at all the cories. going to try to find a peat pot to soften that water off. My tap comes out fairly high. While I am at it I guess I should find out what the correct pH is. I had a breeding colony of bronze corydoras on monthly water changes for years, little pile of leaves off the anubias probably made the breeding so successful. Eventually they got old and started dropping off, and I bought a few to keep the younger ones company and they were carrying a disease I never identified and I lost the whole bunch. I have no idea what the "correct" conditions are. Guess I will check. Pretty sure a pH of 8.0 wasn't happening in my old tank...

"I bought a few to keep the younger ones company and they were carrying a disease I never identified and I lost the whole bunch"

That's the first clue, IMO

Why is the ph such an issue as far as WC's go? What ph is your tap water, after letting a sample sit for 24H?

No heater in the tank? 66F inside my house would make me turn blue, not pink, TBH...

What's the average temp of the tank?

And, as you may already know, it's best to keep fish that are compatible with the source water ph we can offer them, rather than trying to manipulate ph levels in that source water to suit fish that need more acidic or akaline levels to thrive than we can easily provide, w/out complicating matters

my tap water comes out a little over 8. I can do another water change when I get back from the auto-shop, before they close I have a truck that needs attention. I will be putting a heater in but I was surprised by the temperature drop last week and it was just one night. I do not leave heaters in tanks in summer here. thermostat fails and cooks em.

Slaphppy7 said:

"I bought a few to keep the younger ones company and they were carrying a disease I never identified and I lost the whole bunch"

That's the first clue, IMO

Why is the ph such an issue as far as WC's go? What ph is your tap water, after letting a sample sit for 24H?

No heater in the tank? 66F inside my house would make me turn blue, not pink, TBH...

What's the average temp of the tank?

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years ago I bought a few sick ones, they all died, that tank got bleached and is still in my shed, and I haven't bought a fish from that store since. Average tank temp about 77 or 78. I don't let samples sit to test them, I guess maybe I could but they don't seem to drop much.

I got these corydoras in March 2022. Their tank mates were the little juliis - who all got blotch and moved to a 10, and the white mollies one of whom spun and the other started to fail. 3rd mollie is the female in a 10. I still think I moved a rock and the fish got stuck but I will have to examine after a significant engine miss is addressed

Alice B said:

my tap water comes out a little over 8. I can do another water change when I get back from the auto-shop, before they close I have a truck that needs attention. I will be putting a heater in but I was surprised by the temperature drop last week and it was just one night. I do not leave heaters in tanks in summer here. thermostat fails and cooks em.

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A little more than 8, after gassing out for 24H?

I don't run heaters in my tanks during the summer here in Texas either, but do leave them in the tanks, unplugged

Hope you get the vehicle issue solved, w/out much financial hurt...I abhor "car troubles"...especially with my truck

Vehicle issue is postponed, shop manager didn't answer and never go to a shop at closing time and expect good work. I dumped some Seafoam in the gas tank, I think it needs plugs, been a couple of years and at least 20K miles.

I was seeing moisture in the heaters this spring so I pulled them intending to seal the where top meets glass when they dried out. I did that last week after the cold night and now I can put heaters back in and not worry about electrocuting my fish.

I will try my pH and the gas out for 24 hours, didn't occur to me. I am always in a hurry. My tap water goes from faucet to tank with Fritz Chlorine/chloramine remover already in the tank.
I will test it.
But water changes do consistently raise pH around here, Kh was moderate the last time I checked it - a long time ago. if I forget water changes for about 3 months kh will be exhausted and the ph drops hard. That's a given. the 4 catfish I see look good. Number 5 also didn't hang out with the rest when I put them in that tank for whatever reason. I am home and can deal with fish now.

Tank is at 8, tap is at 8, I found a spot to gas out my water sample that I think my cat can't find to dump it. Results tomorrow.

And I only have 4 corydoras catfish in there, no body on the 5th one, I had that tank all dressed up pretty for the photo contest and because sponge filters are ugly. I don't know when he died but I can't even find a skeleton, probably the one staying off by itself. I think all 5 were there in June or July, but I stay really busy and I've been feeding and water changing without much observation.

No one is tippy today, no sign of injury, going to do another water change, it's already at 8, doesn't matter, and the article on FishLore gave a range of pH from 6 to 8, I've had them live at the whole range, temp 73 to 79. 66 was chilly. But there is no ich in my tanks so they didn't get sick. not a sign of fin rot or anything. I'll attach a pic in a minute

So here is the big question. Since the picture is blurry, what species is that? Is it C. aeneus?

It matters a whole lot, because in nature, aeneus lives in waters of 17ºC - 26ºC (62.ºF - 78.8ºF). So if that's the species, your 66f is not shocking, but is a cool end of the range. It isn't for nothing that C aeneus was popular before the invention of aquarium heaters.

pH isn't important except that it reflects hardness, which can be. Nitrate like that is important. Very.

Forget doctoring the water and playing with pH, since it's a red herring. Do the needed water changes, and do them often. Corydoras aeneus will adapt. Looking at Corydoras World, Ian Fuller's solidly researched site on Corys (the best I have seen), you get GH, 2-12, KH 3-6, Conductivity 25 to 350ppm. That is a very adaptible species.

I'm thinking you should go with the crushing scenario, and watch like a hawk. That is, after major water changes, very very soon.

Agree totally with @GaryE above. Would also note that the substrate is going to cause the cories stress, and while this would not cause death, it is still stress and that weakens the fish allowing other factors to harm them more.

I did another 50% water change, ph holding at 8. I thought they liked it cool. They are bronze, Aeneas. I added a sanded for them today, but am still nice rounded light gravel for undergravel filtration. I am really old school. One laid on its side and I took its picture. I also reduced agitation by going down to one sponge filter and the ugly lift tube. I'll bleach the other filter in case number 5, the missing fish had anything.

I want them to lay eggs and nice leaves scattered on the bottom used to work, but I had anubias leaves then, and right now my anubias are young

Byron said:

Agree totally with @GaryE above. Would also note that the substrate is going to cause the cories stress, and while this would not cause death, it is still stress and that weakens the fish allowing other factors to harm them more.

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Bingo Byron. When I was raising Corydoras on undergravel filter my gravel was larger. Part of what is in this tank was too small. Fed, saw a cory having an apparent seizure, watched it spit a tiny piece of gravel out of its gill. I've pulled the fish, am removing the gravel, I'll run it thru a colander and just use the larger stuff.

And half of the tank is sanded. I'll feed on that side. It's thin, I don't want hydrogen sulfide buildup but they are enjoying it. Because I've seen other posts on here with tippy corydoras and I found a cause, I changed the title. In case someone else has cory problems. thank you all for your information, I have a feeling these 4 will be fine.