Black Skirt Tetra Problems

[-Nemo-]

I've had these two for about a month now, and about a week ago the larger of the two developed white spots on its caudal fin only the next day they became larger and at the base of his fin a large white spot had appeared with a red tint to it, almost looking swollen. I thought it was Ich, and have since been doing treatments. The swelling and redness at the base of the tail has left, but that white spot is still there, as well as the others. It hasn't gotten any worse, but also not really any better.

My smaller tetra, about a day after i started treatment, developed two very small white spots, but they have almost gone away now.

After reading more about ich, it says the spots are usually very small, but these are bigger. Any clue what it might be? I'll try and post pictures later. Also i might mention, none of the other fish have been affected at all.

Thanks for any help.

 

[-Nemo-]

Managed to get a semi-good picture of what i'm talking about on the larger tetra. He wouldn't stop moving around

 

[-Nemo-]

anyone?

 

[NEONCORY]

Are they spat at each other? I mean do they fight? Some of the tetras spat at each other all the time. Even the small Neons do that. When the other fish come to the area the fish consider his/her territory, they go try to peck the other fish and try to chase away. This especially happen more often when there is only the small number of their kind in the tank.
For example, if there are only 2 of them one is stronger than the other. And stronger one always pick the other fish. But when you keep 5 or 6, the strongest could pick any other fish. The aggression will spread out instead of always the one fish get picked on.
Judgeing from the picture, the white spot could be the bruse from the pecking or hitting. Or it could be some kind of fungus thing. Hard to tell.
Either way, treat with the antibiotic and extra water change would be good. So the bruse, bump or deasease would get treated. Since we are not exactly sure about the simptom or cause, I would not treat full strength but maybe 1/2 the recommended dose. You can always go up but it would be too late to go down the dose if something goes wrong. Also, you have many tankmates. You probably ought to move the fish and treat.
You might want to look the deasease or sickness picture and treatment from the book or internet. Before take any action. Since I am far from the expert of diagnosing the illness of the fish.
And I'm sure people would like to know all the basic information before effectively help you. Like water parameter(ph, dh, temperature), tank size, all the tank mates, feeding(frequency and volume), filter and water change.,etc.
I'm sorry I can't be more of a help but you haven't give enough to go on.