Male A Agassizii

[Neptune's Neighborhood]

So I've had this male Apisto Agassizii for.. maybe 5 months. Anyway back in the beginning he got some damage to his lip and I thought he had columnaris. Took three separate treatments of maracyn i & ii to get whatever it was to go away. He was in QT the whole time.

I moved him into a 20L with a female and a couple pencilfish.
dgH 0, dkH 3, pH around 6.6-7 I use straight RO water, weekly 40% water changes
temp 78 F, NH3 0, NO2 0, NO3 negligible
The water is fine because the other fish are flourishing, the female agassizii has nearly doubled in size.

The problem is, this guy constantly digs a little hole and just lays in it. Sometimes he lays crooked, other times he lays flat. He barely does anything. But, he doesn't really hide. He doesn't eat, I can literally drop food onto his face with a dropper and he doesn't care. He doesn't seem to mind when I put my hand in there to pick him up for treatment or just to make sure he's breathing. He's probably lost maybe 1/3 of his weight since I got him over his lip thing. He damages himself on driftwood sometimes and I'll use some pimafix on him and he never seems to have an infection or fuzziness. He's just.. terrible. I don't know what's wrong with him, but I've nearly given up.

What can I do to troubleshoot this? Video from this morning, sorry about the algae

video - http://flic.kr/p/e47EKR

 

[Mike Wise]

I fear that you have an internal bacterial problem and your male is probably too far gone to save. Although Mardel makes some excellent products, Maracyn (Erythomycin) and Maracyn II (Minocycline) are not especially effective against such internal problems.

 

[Neptune's Neighborhood]

I fear that you have an internal bacterial problem and your male is probably too far gone to save. Although Mardel makes some excellent products, Maracyn (Erythomycin) and Maracyn II (Minocycline) are not especially effective against such internal problems.

Should I QT him? Euthenize? What about the other fish he's been with?

 

[Neptune's Neighborhood]

after months of struggle, he passed overnight. Are the others in danger?