Postmortem for dwarf cory

outofwater

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Just would like any thoughts/opinions on this. My tank has been firmly established now for 3 months, and this little guy was there from the start.

A few days ago I found him dead early in the morning. Pictures were taken as soon as I noticed and pulled him out.

The day before I had not noticed anything wrong. I feed the fish twice a day (morning and early evening) and always give them a last look around before going to bed, nothing abnormal, all fish were swimming, eating and behaving as always.

I did an 80% water change after this, both as a prophylactic measure and also because the tank was due for its monthly "deep clean" besides the usual weekly water change (25%).

Water parameters were checked the morning after I found him: ammonia and nitrites at zero, nitrates at 20, water temp around 76°F, and pH stable around 7, which is where this and my other tanks always are at.

Tank mates include 5 other corys, an otto, 7 neon tetras, 2 mystery snails and an assassin snail that every time I think had finally kicked the bucket and I try to look for his carcass, resurfaces from the depths of the substrate.

Thanks in advance, just wanting to see outsiders thoughts in case I can improve or prevent something.
 

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Colin_T

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Does it have whiskers (I can't see them)?

The fish looks a bit pink on the bottom half of its body. This can be caused by poor water quality or something on the substrate irritating the fish (blue green algae or sediment/ gunk).

The fish's gills seem to be flared out a bit and this can be something in the water or the fish had a heart attack or stroke.

The fins look a bit clamped and rounded off, again possibly water quality.

Is there a thin red hair like thing sticking out of its butt?
If yes, then it has intestinal worms (Camallanus or Capillaria) and the tank should be treated. The worms don't normally kill fish but they do weaken the fish and reduce its blood level and pressure, which increases the risk of heart problems.
 
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outofwater

outofwater

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Does it have whiskers (I can't see them)?

The fish looks a bit pink on the bottom half of its body. This can be caused by poor water quality or something on the substrate irritating the fish (blue green algae or sediment/ gunk).

The fish's gills seem to be flared out a bit and this can be something in the water or the fish had a heart attack or stroke.

The fins look a bit clamped and rounded off, again possibly water quality.

Is there a thin red hair like thing sticking out of its butt?
If yes, then it has intestinal worms (Camallanus or Capillaria) and the tank should be treated. The worms don't normally kill fish but they do weaken the fish and reduce its blood level and pressure, which increases the risk of heart problems.
Thanks Colin. Whiskers had been damaged from the start (I had started this tank with gravel and later switched to sand precisely for the cories). His whiskers never fully recovered.

Substrate is vacuumed every week during water change, had been having a bit of algae issue (on glass, other surfaces and plants) which has improved by reducing intensity and length of light period in last 2 weeks.

I can't explain that coloration on bottom of body, but there was nothing sticking out of his butt, it might be the lighting on the picture or an extension of that "irritation" that seems present on the rest of the bottom of his body.

As for water quality I can say the water is as good as its always been. I test every week or two now just to keep an eye on it and it always is at 0 ammonia and nitrites, nitrates range from 5 to 20 depending on what time of week I test, pH remains around 7, and temp ranges from 76 to 78 some days, depending on room temp. Some days the heat still kicks in the apartment.

Here are a couple of pics of a couple of the remaining cories, for reference.
 

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DoubleDutch

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You call it a dwarf Cory but exact what species is it. Looks like a C.aeneus
 
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outofwater

outofwater

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. At the shop the sold sold all to me as "pygmies" because they were too lazy to check... worked for me.
Honestly I think you nailed it and it was a male bronze cory, very very small though, compared to the females and the other cories I keep. Is that how different they are in size compared to females?

And yeah, I'll be getting more of all of them soon (cories, neon tetras and ottos) just waiting for the spring weather to firmly establish itself here, I don't want another repeat of my last attempt to stock this tank.
 

Essjay

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The photo on the left of the three ( the one with the red behind the moss) isn't a pygmy cory either, if you were sold that as a pygmy. I don't know what it is, just that it's not a Corydoras pygmaeus.
 
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outofwater

outofwater

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The photo on the left of the three ( the one with the red behind the moss) isn't a pygmy cory either, if you were sold that as a pygmy. I don't know what it is, just that it's not a Corydoras pygmaeus.
Yeah as I said lazy lfs. It worked for me as they had the pygmies priced around half the regular ones 🤷🏻‍♂️

anyway, it's a peppered/pepper cory (Corydoras paleatus), often confused with the "salt and pepper" ones. I've started to appreciate the scientific naming because otherwise confusion abounds for both fish and plants
 

itiwhetu

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. At the shop the sold sold all to me as "pygmies" because they were too lazy to check... worked for me.
Honestly I think you nailed it and it was a male bronze cory, very very small though, compared to the females and the other cories I keep. Is that how different they are in size compared to females?

And yeah, I'll be getting more of all of them soon (cories, neon tetras and ottos) just waiting for the spring weather to firmly establish itself here, I don't want another repeat of my last attempt to stock this tank.
It is up to the purchaser to identify the fish they are getting, remember the fish shop is only trying to make money and get a sale.
 

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