Can anyone tell from these pictures why my Cory died?

[Supercoley1]

I bought 6 black cory schultzei 6 weeks ago and they have been great. However last night I found this one (I think female - about 2 inches and broad.)

She was floating at the surface mouth upward. The other 5 are OK and feeding as per usual:

As you can see from the pics she was very fat but then so are a few of the others. From reading I assumed this was pretty normal as they do eat even when there is nothing to eat???? I have been dropping a few boiled & shelled peas once a week in case of constipation. Their other foods are flake daily. algae pellets every other day and frozen bloodworm once a week.

They are all in a heavily planted 33USG tank with 12 microrasboras and 50+ cherry shrimp (they don't stop breeding.) All other inhabitants are fine and dandy. Temperature is between 24ºC and 25ºC.

The pics are below:



Any advice/observations would be gratefully received.

AC

[MatsP]

It looks like it got "internal bacterial infection" - this is not that unusual, and is generally caused by "stress" in some form, such as bad water conditions, too low or high temperature, but it's hard to say for sure.

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Mats

[Mike_Noren]

Well I know I don't have everyone with me on this, but I'd stop feeding frozen bloodworms (by which I mean chironomid larvae, not tubifex).
My experience is that I never, ever have fish contract dropsy unless I feed frozen bloodworms, if I do it shows up regularly.

Sure the fish loves it, sure it's a natural food for fish like cories, but the problem is poor handling of the bloodworms after collection and before freezing - they're left to die and start to rot, so unless they've been thoroughly irradiated you're feeding a mush full of opportunistic bacteria to your fish. Some brands are better, some are worse, but in my opinion you're playing russian roulette with your fish every time you feed frozen bloodworms.

[Supercoley1]

Can I use Waterlife Sterazin with corys and shrimp in the tank? I have some of that.

Andy

[MatsP]

If we look at this page:
http://www.waterlife.co.uk/waterlife/sterazin.htm

I'd say no - and it would certainly not help against the problem this fish has, as it's not a internal parasite, but a bacterial infection.

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Mats

[Atlantis Child]

I didn't know there was medication for internal parasites. Does it work? How do you know if they have any in them?

I thought you couldn't know it was there or treat it, and it was a possible cause of 'mystery deaths.'


-Atlantis