Help! Red Spot on Pygmy Corydoras

[CorydorasEthan]

I noticed a red spot on one of my pygmy cory's underside. It is acting normally, but I am concerned it might be a disease of some sort. I read somewhere that it's an infection, but don't know what to do about it. Any ideas? Thanks. 

Parameters seem to be as follows:

- 75 GH

- 75 Nitrate

- 0 Nitrite

- 0 Cl

- 0 Carbonate 

- 6.4 ph

Edited August 29, 2021 by CorydorasEthan

[Keeg]

The red spot looks like it is contained to the fish's anus. Please correct me if im wrong. 

Based on this, I would assume this is an internal bacterial infection or internal parasites. Do you see any red strings coming out from the anus when the fish doesn't move? Is the area swollen? 

You might be better off with quarantining this fish and any others if they're showing similar symptoms. Then dosing the med trio to be safe on all guards. But if it truly is internal parasites, then this will be a whole different conversation. 

[CorydorasEthan]

On 8/29/2021 at 7:17 AM, Nooby said:

@Keegif it’s internal parasites, wouldn’t all the corys have it and are they wild caught?

I do not know if they are wild caught. They've been in the tank for almost a year now, with no problems.

[Keeg]

On 8/29/2021 at 5:17 AM, Nooby said:

@Keegif it’s internal parasites, wouldn’t all the corys have it and are they wild caught?

Not necessarily, kind of like how ich can be on one fish or a couple and not at all on others. 

[Torrey]

I would quarantine the affected corydora. 

Fish (and pretty much all animals, including humans) can regularly have 'harmful bacteria' and parasites and we will never know, until a stressor disrupts homeostasis, and we see evidence that there is a problem. 

 

Have there been any changes that could have elevated the amount of stress?

Anything from a new tank mate, to an aggressive water change, to accidentally leaving the lights on for too long, or a nitrate spike can be the one extra stress that weakens a fish.

My solution is typically Q/T, identify issue, treat accordingly, and determine how to eliminate the stressor so the issue doesn't repeat.

[CorydorasEthan]

On 8/30/2021 at 1:19 AM, Torrey said:

I would quarantine the affected corydora. 

Fish (and pretty much all animals, including humans) can regularly have 'harmful bacteria' and parasites and we will never know, until a stressor disrupts homeostasis, and we see evidence that there is a problem. 

 

Have there been any changes that could have elevated the amount of stress?

Anything from a new tank mate, to an aggressive water change, to accidentally leaving the lights on for too long, or a nitrate spike can be the one extra stress that weakens a fish.

My solution is typically Q/T, identify issue, treat accordingly, and determine how to eliminate the stressor so the issue doesn't repeat.

Yeah I added a few otocinclus, two if which died in the first day. The other is doing fine. However, I think the infection might have been there before that. Maybe I left the lights on too long. 

[CorydorasEthan]

I regret to inform you that the cory died today. And I just picked up Erythromycin and Melafix. Pretty disappointed, but next time I'll be ready. 

On 8/30/2021 at 9:31 AM, Nooby said:

@CorydorasEthan best to figure out the cause for the death, it is weird to lose both within a day

Yeah I checked with the store and apparently it was a condition within their tank. I am closely monitoring the other fish in the tank for any symptoms of disease.