Strange Cory Behaviour

[Amunet]

A few weeks ago, I started to notice one of the spoted cories swimming around the middle of the tank. This particular one was the newest addition to the tank & I know when we got it, it's barbells were almost gone. Well when I spotted it again, they were completely gone.
I kept an eye on it every day, and it looked like it would search around for food like usual, but it would always swim around the middle.
Well it did get worse, so I put it into a breeder's net where it eventually died.

Now some of our skunks are doing the same thing. They were also purchased w/ barely any barbells, and now... well.. they still have a little bit but they're starting to hover over the gravel as well & I'm just afraid that they're going to end up like the little spotted one that died.
The rest of the spotted cory are totally fine I should add. They stay on the bottom, their barbells are nice and long and they look totally healthy.

I know I know, we should've made sure the ones we purchased were healthy, hindsight is 20/20.... I'm just worried about saving the ones we have now.
Or is there nothing I can do?

I make sure the gravel is vac'd every time I do a weekly water change. The gravel is a mixture of small smooth gravel w/ eco-complete. Nothing sharp on the bottom or anywhere in the tank. All water stats are normal.

 

[jollysue]

If they were mine, I would take that empty 5 gallon and make a nice little hospital, with at the most a fine sprinkling of sand. Then I would treat them with a good antibiotic, a Mardel product if you are in the States. I would have to research my choice of which of their products to use. I might even call them for their recommendation. I would keep the bottom vacummed of left overs. They find food with their barbells which are sensitive like fingers. So when they are damaged they are at a disadvantage.

Make sure they are getting food, the left overs are getting cleaned up, and that the infection is clearing up. That is what I would do. And I would do everything to clear up the infection. When the infection is resolved, just like any other tissue loss, it will recover, but may not return to the former glory.

I would also add a little cloth plant cover and keep the lights dim often. You might try some antibiotic food. Or one of the GelTec antibiotic gels. I usually feed it in addition to the food, figuring they get some. I actually like the GelTec Ultimate grow XL. Or something like that.