Cory With A Red Belly Unable To Stay Upright Or Steer

I have a new cory problem. I'm starting to be worried that whatever's wrong with this cory, it might be contagious, since he was a replacement for the last fish that the LFS guy said sounded like had a swim bladder problem.


I have four Peppered cories, three of which I bought six days ago, and one that was a replacement for the fourth that died two days ago. One of them, when I got him, wasn't behaving quite normally: he would skulk in the back of the tank and didn't shoal with the other three, sometimes resting in the plants for long periods of time without moving. I came home two days ago to find him floating upside down at the bottom of the tank. He'd make a mad dash for the top, get tired, and slowly sink back down. I noticed that his gill and chin area were very red. Two hours later, he died.

I went back to the store and got a replacement (after they checked my water parameters themselves and found them fine). Now the new cory is acting suspicious. He's red all along the paler areas of his lower sides and underbelly, and he's swimming erratically up and down, not quite able to steer himself quite right. Sometimes he floats upside down, too.

The other cories seem to be just fine.

Is this swim bladder issues, or something scarier? What can I do?

Cory diet: fish flakes, shrimp pellets, and blanched butter lettuce leaves (they don't seem to eat the shelled, frozen peas I give them)

Tank size: 10 gallon
pH: 8.5
ammonia: 0
nitrite: 0
nitrate: 30
tank temp: 76 F
Tank age: cycled for 2 months, first week with fish.

how are the other fish? the fact that this cory is quite obviously showing illness means that you need to treat it. Do you have a hospital tank? If not, you need to get some broad spectrum anti-bacterial medication in the tank. Do a water change first. He may be ok, maybe not. If he does pass away dont get another from the same lfs.
What does the redness look like - does it look like lots of tiny veins showing creating the look of red skin? Or is it like a burn?
If you soak the peas in garlic he may well eat them. Are you deshelling and chopping into very fine pieces?

Red fish was dead this morning. Once they turn red and stop being able to swim, it looks like they tend to go downhill pretty fast. I think the other fish are okay. Although I can't find my smaller guy this morning, so I hope he's not lurking in the back of the tank somewhere, feeling poorly.

The redness doesn't look like veins, it's just a dark red against the "pepper" of his skin. Looks like a red gill slit, but along his belly, too.

Won't an antibacterial in the water kill my filter bacteria?

Sorry to hear you're cories aren't good.

Some Bacterial treatments can knock your stats about,depends what you use...

I would ask in the emergency section,wilder will be able to help and is a wizz at different meds etc

Good luck with the others,sorry i couldn't help.

Thanks, Harlequins--but I DID ask in the emergency section and NOBODY has answered.

I just wish I knew what was causing this . . .