Help With My Cory Cats Please
I have four false julii cory cats that I've recently isolated in a 5.5 gallon tank, which will be temporary. There is no substrate or plants, and only some decorations. The reason for isolation is threefold:
1) all cats have lost their whisker. I've had them since about October of last year and they were doing really well. Some of the small ones lost their barbels right away but the two bigger/stronger cats managed to hold on to theirs for a few months longer. I had read that they can grow back, and patiently waited. Two of them looked like they were going to grow theirs back, but the little nubs were quickly worn down to nothing again. Aside from some redness, they appear to be in full health.
2) two of them seem to have trouble with buoyancy. They'll sit still for a short of time and will roll over or just start letting themselves go with the current in the water. They look weak when they do this. The other two don't do this. If I approach the tank sometimes they'll quickly go back to swimming like their fellow tank mates. This may just be a quirk of their personality, but either way I wanted to see if their whiskers will come back so they're also in isolation. If anyone has any thoughts on this, please share.
3) one of the ones with a buoyancy problem has been in a poor health for the last little while, but he's a little fighter. His barbels are completely gone and there was a lot of redness on his mouth, and lately I've noticed that his fins seem a bit tattered and that his belly looks like it's scraped across some of the lava rock in the main tank. He also sometimes looks bloated and like his eyes are bugging out. When he looks bloated, I've removed him from the tank and fasted him and then he seems to return to normal size, but no improvement is seen anywhere else on him. I'm thinking he's got a fungal problem, though none of the other fish are displaying this.
Also worth noting, I had a bad outbreak of BGA, and fought it off with API erythromycin. The tank was dosed for four days, and in those days the outward condition of the one fish mentioned in (3) seemed to improve.
I am planning on changing the substrate in my main planted tank to sand and will be removing the lava rock. I don't believe it was the substrate that caused the erosion because the gravel is rounded, not at all sharp or jagged. Another reader suggested that it may be the lava rocks so I am looking to replace them.
The new substrate will be flourite sand and dark.
Other tank mates are: 7 tetra, 5 celestial pearl danios, 3 oto cats, 1 rubberlip pleco. None of them show any signs of illness.
Water parameters are what they should be, the last time I checked the only thing displaying was nitrate at 10ppm, which I try to keep stable for my plants. Water changes occur once a week.
So my questions are:
1. Is there an effective broad spectrum antibiotic and/or anti-fungal I should be looking for with regards to my little cory?
2. Even though a couple of months have passed, will their barbels grow back? I'm hopeful.