Pygmy Cory - Not Thriving

On removing an ornament from the main tank to put into the QT ( which is now housing some new harlequin rasboras ), I noticed that one of the pygmy cories (which I've had for 5mths) had been hiding inside the ornament. Although there is some noticeable variation in size and colour of my pygmy cories, the one that had been hiding inside the ornament looks particularly small, if not smaller than he used to be, and rather "washed-up" like he's a black garment that's been through the washing machine too many times. Lately, I'd had trouble finding all 6 at once, although usually managed to do so - but now wonder if the cory that has been hidden regularly in the corner near the heater has been the same one and this one, and that he has possibly been making a habit of hiding inside this ornament.

This evening, he did move about a little for a swim along the front of the glass which is an improvement on yesterday - but, on inspecting him, his barbels look very short (although this could be that he just looks smaller all over), and I wasn't convinced that one of his eyes was functioning properly (although I can't be certain about this). There is some redness inside near his vent which I think looks like some red poo is about to come out - and could be accounted for by red-coloured food, if indeed he has actually eaten anything.

I'm not able to be very specific - apologies about this - but wondered if anyone had any suggestions for converting him from 'surviving' (barely) to 'thriving' once again?  [This is where a dose of aquarium salt worked wonders on goldfish but I know isn't appropriate for cories - and not when the other tankmates all seem fine (touchwood).]

I do weekly water changes - the new siphon is quite strong in comparison with its predecessor and so the water changes have tended to be 40% lately. Water parameters seem to be consistent with ammonia and nitrite at 0, nitrates never higher than 15, PH 6.4, water is very soft but some Tuffa rock is keeping it from being overly so. Substrate is Unipac tana. Food is a mix of good quality flake and micro pellets, with some occasional Tetra Delica daphnia - the cories have been able to get more than their fair share of food in recent weeks as the x-ray tetras have been less interested in food than usual (albeit behaving fine) and therefore more has been falling to the substrate.

Thanks in advance for any suggestions you can offer.

I lost one of my corydoras hasbrosus (salt and pepper) a few weeks ago while I was away.
Through stupidity on my part too. The fence I made for the tank I had pushed up against the glass but somehow this little one had managed to get himself jammed between the fence and the glass and my husband didn't notice (to be fair he did blend in well with the stones).
It meant I have just the one left and they are so pretty.  I am planning on getting another two on my journey home from a camping trip next week (Kesgrave's)  to keep my "baby" company
However, having got the other half to agree to camp in that direction purely so we could stop on the way home, and having planned the break to allow for the fact that they don't open on Mondays the little b****r disappeared.
I searched that tank thoroughly, peered in, around and even under! but he was missing. Well no point in buying those particular fish then and it's better to be understocked.
24 hours later it reappears looking very jaunty and was quite active.
I bet you anything you like I shall buy a couple more and he disappears for real next time, when I won't be here to see what's happening.
I'm taking a chance that I can leave them for 5 days to look after themselves.

Thanks, folks, and particularly Sue with her experience of pygmy cories. I thnk there'd be no harm in trying the eSHa 2000 - the only problem is that the second tank (QT) is now housing the new harlequins, so I don't have a spare one... and there's absolutely no way that I can get a 3rd tank as my husband is already getting nervous that the second tank (QT) is going to become a permanent fixture.

Would temporarily moving the pygmy cory in the tank water into a small plastic container to dose the eSHa 2000 be an option? This would mean no filter and no heater, but we do live in a warm flat, so perhaps wrapping a towel round the plastic container to retain the heat, and keeping the cory in there for an hour or so might be an option? I could keep an eye on the temperature if I moved the thermometer in there.

If this doesn't work out, then this is somewhat reassuring that sometimes these situations are outwith our control ie that there's no point in blaming ourselves, no matter how tempting it is to keep wondering if the situation could somehow have been avoided.

As an update, I put him in a container with the medication and left him in there for 1hr,55mins, at which point I noticed he was starting to go belly-up, even although he'd been perking up an hour beforehand. In a panic that he was suffering from lack of oxygen, I moved him into the main tank, where he made a beeline for the filter in the opposite end of the tank to his usual position, as though on some sort of suicide mission to get inside it.  This morning, he was surrounded by the other cories keeping a vigil/holding a 'wake' and I didn't expect him to be alive on my return from a hospital apptmt - but he is.  Who knows what will happen next - but I think he's probably best in with his tankmates for now, even although his washed-out colour looks like a ghostly apparition.

Sorry to hear that FCMF.

Glad to hear that. If it makes you feel any better, I was reading this month's PFK magazine and a chap on there who kept over 30 varieties of Corydora said that C. Habrosus is the one species he's had no success with, so don't feel too disheartened!

I bought 4 last week as well, all the shop had in. They are a lot more outgoing than the 6 pygmies though.