Ill corys

[Troender]

I've posted this on other forums, but noone seems to know an answer. It's not puffer related, but I am getting desperate pretty soon. Maybe someone in here knows an answer anyway? I think I get all the strange illnesses, that noone seems to know the answers to. The expert on fish illnesses in the Norwegain forum I usually ask those questions, hasn't even answered this one. He must have given up on me now. Why can't I just get fin rot or ich? That would have been a lot easier to deal with! I can't remember having ich on any fish for years!
Well, that was a bit of complaining (sorry about that. It's 2 am here. Just a bit tired). Now the story. A little copy and paste, and here it is:
I've got two c. sterbai that has been ill for some time. Those are two of a party of 7 wild caught sterbais. I've had them for a little more than a year. They are in a 130 liters community tank, with mostly peaceful fishes. The tank is a bit overstacked, but is very well filtered, with both an external and an internal filter. The external filter has been up and running for more than a year, and the internal filter for a month or two.

Here's the problem, and it's a rather long story. Two of the corys got a bit darker color more than a month ago. Their fins was a bit split up and a bit ragged. One got some problem with its balance, and in the end dug into the sand to prevent itself from falling over. They both seemed out of mood. The other fishes (except one non-cory - I will explain later), on the other hand, has been in very good shape, and the other sterbais has even delivered two rounds of an awful lot of eggs (which now is fry - but they are moved to another tank), and will probably start again in a few days. The balance problem came right before Christmas. As I was going away for the holidays, I gave them Flubenol in despair a few days before leaving. That seemed to help. They got their moods back, and the balance problem seemed to go away. But they didn't get well. They are still darker in color, and I've realized that they have breathe a lot more rapidly than the other corys. The fin problem disappeared on one of them, and this week the other cory seemed to have its fins healing as well. But tonight it seems worse again. And they are both thin. They have good apetite, and eat like the others. I've seen them eat, and they don't spit the food out. The last two days I've given them discus food (usually they get a very varied diet), which they have eaten heartily, but still they get thinner and thinner, day by day (I can see the difference in just a day!). So there you have it: they act like they are well (except for the breathing), but look very much like they aren't.

Besides the Flubenol (and, no, I didn't underdose it. I always overdose a lot!), the tank also has been through two rounds of other meds: Esha 2000 (which helps on infections from bacteria and fungus), and Esha Hexamita which helps against the same as Esha 2000, plus hexamita. Neither of the two Esha meds kill the bacteria in the filter, so there's been no filter crash because of it. Those two meds was used before the Flubenol, and was because of a very ill cichlid, who seemed to have hole-in-the-head disease. The cichlid didn't make it. The meds seemed to help, but the injuries was probably too severe for it to survive anyway.

Here's my water parameters:
PH: 7,3 - I know it's too high. We have depressingly 8.6 in the tap water - not the best for people who mostly deals with South-American fish (except my puffers, of course), like I do.
GH: 5-6
KH: 2-3
NO2: 0
NH3/NH4: 0
NO3: Well a bit high, but not alarmingly high.
Temperature: 25-26 degrees Celcius.

It's sand at the bottom of the tank. I am bad enough to take water directly from the tap into the tank, and that means I use heated water. I know that can bring trouble, but I would have thought I would see any trouble with my puffers first, if there was a problem with it. I usually don't add anything to the water, as there's no clorine in the tap water. Well, there's usually no clorine in the water, but there's been the last week - probably because of a lot of rain in the area. But the trouble started long before the clorine was an issue.

Anyone who can help? I don't want to lose those two!

[crazedpuffer]

It could be age and that there immune system is slowly giving out. That's about all I can come up with.

[Agnate]

"The last two days I've given them discus food (usually they get a very varied diet), which they have eaten heartily, but still they get thinner and thinner, day by day"

Is it maybe internal parasites of some sort, especially since you said they were wild-caught. I don't know much about illnesses, but it would explain their unhappiness, the sunken stomachs, and the fact that they don't have tons of energy (as the parasites take all of the nutrients).

*Shrug*

[Troender]

Corys get IPs very, very rarely. Actually, I've never heard about a cory that's had IPs. BTW, the Flubenol should have taken the IPs if there were any.
Last night I gave them a new dose of Flubenol. As it helped (but did not cure them) last time, I hoped that it would help enough to keep them going until someone could give me an answer. But this time it has not helped. And now the situation for one of the ille fishes has worsened a bit. Today, for the first time, she didn't come around when I fed them - even though they got their favourite food: bloodworms. She didn't want anything to eat before some bloodworms landed right before her nose. I am happy she ate those bloodworms. Then she hasn't stopped eating totally.

[CtHM]

Sad. I agree with Flames. It's possible they may be a little old, or possible just have immunity problems from being wild caught. I'm not sure =/