Injured corydora

@NCaquatics , what do you think? I'd worry about the cory getting stressed and darting about in a three litre cube, perhaps it would be safer to move the bamboo shrimp and snail into the 3 litre, and treat the cory and tetra in the main tank? Doesn't look as though we're dealing with a contagious disease like a virus or parasite.

At the risk of repeating myself...I would leave the cory alone. Do substantial water changes on the main tank, daily, or alternate days, for a week. Add only a good conditioner. Most times this is all you need.

Unless you can ID the specific issue, any treatment beyond the above is risking the fish. Chasing it around the tank to net it and move it into yet another different environment is the most sever stress we can inflict on a fish, because it evokes the "escape predator" response. This will seriously weaken this fish further. And salt is not going to do anything unless this is something that responds to salt, and I've no idea on that.

As for "healing," the issue is to provide a clean environment and nature will do this. Fins can regenerate depending upon the issue, but that is frankly irrelevant--the issue is to restore the health of the fish without further compromise.

@Byron : Thanks. That's what my takeway from your last post however my only concern is that it's an infection that I need to treat. Or risk of it infecting other fish.
I think @NCaquatics mentioned there is some infection setting in, do you think the latest pictures suggests it would be fine to leave her as is?

She seems to be active despite the situation and I really don't want to risk shock moving her to another environment.
I don't have space for a proper 10G+ quarantine tank unfortunately and I am worried that the corydoras will not do well in the tiny "tank" I have.

I am already on top of my water changes. I currently change 30% every 2 days and 50-60% on weekends. The water parameters (Ammonia 0, Nitrite 0, Nitrate 25ppm) is as good as it can be.

I've got some API Aquarium salt which I haven't used but from some research this is not a treatment, it's simply to help replenish any electrolytes.
Again it seems nerrite snails and bamboo shrimp tolerates them but from the description I am not sure if it will help the corydoras's situation.

Api Aquarium Salt is an all natural salt, made from evaporated sea water which promotes healthy gill function, reduces stress and loss of electrolytes. It may be used to improve the efficiency of medications and reduce the harmful effects of nitrite.

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jonnyc88 said:

@Byron : Thanks. That's what my takeway from your last post however my only concern is that it's an infection that I need to treat. Or risk of it infecting other fish.
I think @NCaquatics mentioned there is some infection setting in, do you think the latest pictures suggests it would be fine to leave her as is?

She seems to be active despite the situation and I really don't want to risk shock moving her to another environment.
I don't have space for a proper 10G+ quarantine tank unfortunately and I am worried that the corydoras will not do well in the tiny "tank" I have.

I am already on top of my water changes. I currently change 30% every 2 days and 50-60% on weekends. The water parameters (Ammonia 0, Nitrite 0, Nitrate 25ppm) is as good as it can be.

I've got some API Aquarium salt which I haven't used but from some research this is not a treatment, it's simply to help replenish any electrolytes.
Again it seems nerrite snails and bamboo shrimp tolerates them but from the description I am not sure if it will help the corydoras's situation.

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I am not an expert on disease, I have little to no experience. But no fish ever got sick or died from clean water. We do water changes for much more than ammonia/nitrite/nitrate. Most but certainly not all fin issues are caused direcxtly or indirectly by the water. We don't know the background of this fish.

Salt is effective for some issues but it is also detrimental. Salt does help with nitrite issues but that is not pertinent here. The "preventative" aspects cited (promote healthy gill function, electrolytes, etc) is not really accurate, as the effect of salt on fresh water fish can easily counter any "benefit," if such exists to begin with and frankly it does not. And I can't see any connection between electrolytes and fin degeneration.

Byron said:

I am not an expert on disease, I have little to no experience. But no fish ever got sick or died from clean water. We do water changes for much more than ammonia/nitrite/nitrate. Most but certainly not all fin issues are caused direcxtly or indirectly by the water. We don't know the background of this fish.

Salt is effective for some issues but it is also detrimental. Salt does help with nitrite issues but that is not pertinent here. The "preventative" aspects cited (promote healthy gill function, electrolytes, etc) is not really accurate, as the effect of salt on fresh water fish can easily counter any "benefit," if such exists to begin with and frankly it does not. And I can't see any connection between electrolytes and fin degeneration.

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I've never had any issues with the corydoras in the tank, even with the Odessa barbs.
However around a week ago one or two were laying eggs and I did notice the barbs chasing after her.
Perhaps the barbs had nipped the dorsal and tail fins by accident. I can't be sure but that's the best guess.
All other fishes in the tank looks healthy. I only have one other fish with an issue few days before the corydoras (https://www.fishforums.net/threads/tetra-swimming-weirdly.462825/page-3#post-3950430) which is currently in a quarantine container. Besides swimming vertically heads up the tetra looks normal.

Appreciate the clean water is important, and I'm certainly a beginner when it comes to fish disease.
I wil ensure the tank water is changed frequently and keep an eye on her.

Id opt to add a couple Indian almond leaves to her tank, they do wonders to help healing. Tannins would be helpful for your neon tetra too.

NCaquatics said:

Id opt to add a couple Indian almond leaves to her tank, they do wonders to help healing. Tannins would be helpful for your neon tetra too.

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Or if you've got some redbush / rooibos tea in the cupboard, you can add a brew of that to provide some beneficial tannins. Known to assist in the healing process.

There is an almond leave already in the tank from Day 1. Perhaps I’ll put a new one in.

Did a big water change today (80%). This Corydoras gave me a fright as she was laying belly up. However when I tried to scoop her she darted away very quickly.

Her dorsal fin seems a bit better today, not as bunched up. Noticed that her side fins are also injured. Which may explain the strange positions. Hope she gets better soon.

Can anyone tell if she’s definitely a female from the belly picture? She doesn’t lay there like that for long, just few minutes then she’ll move to another position.

Shes definitely female.

Does not look good unfortunately for her

If she has been nipped, why would that cause her to suffer so much and potentially kill her? Is it literally the stress/shock?

Infection setting in. Any open wound can become infected

Hmm I'm getting contradicting messages here ...
Should I euthanise her?
She is swimming around and I saw her eating. To me she is recovering but @NCaquatics seem to suggest that she is on the way out?

This is a picture of her upright. She is definitely eating. To me her dorsal fin seems to be improving, it’s more extended then before.
When I tried to catch her with net earlier she was very quick evading.
Again, to my novice eyes I think she has a fighting chance.

jonnyc88 said:

Hmm I'm getting contradicting messages here ...
Should I euthanise her?
She is swimming around and I saw her eating. To me she is recovering but @NCaquatics seem to suggest that she is on the way out?

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I don't think NC was suggesting you euthanise her. Just that especially with her lying on her back, she doesn't look great, so try to keep your hopes in check. Keep trying by all means, just be prepared that she might not make it.

jonnyc88 said:

This is a picture of her upright. She is definitely eating. To me her dorsal fin seems to be improving, it’s more extended then before.
When I tried to catch her with net earlier she was very quick evading.
Again, to my novice eyes I think she has a fighting chance.

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You see her more than we do, and when a fish is still eating, it's still fighting, and have seen fish recover even when they looked worse, so she still has a chance.

But why were you trying to net her? That's only going to cause additional stress that she really doesn't need right now.