fin rot

[the_dougie]

my betta has a fair bit of black "blotches" on one of his pectoral fins. I've been treating it with this fin rot cure. I've been following instructions for a week now but it seems to be getting worse, not better. how long do most medications take?
also, it's just on one of his fins. Fin rot would affect all of his fins...wouldnt it?

[Blinky]

Fin rot doesn't usually show up as black patches - it looks whitish, and the fin rapidly rots away. Can you post a picture of your betta's fin? Maybe that way someone can identify the condition.
Fungus and bacteria can affect just one part of a fish. I lost a cory earlier this year, he injured a fin and fungus set in. It stayed on that fin and grew (despite treatment) until it reached his body, and quickly killed him.
What, exactly, is happening? Is your betta's fin getting smaller, like it's rotting away? Or is it covered in black dots (black spot disease, a parasite) that are increasing in number? How is he acting - is he eating, swimming normally, etc?
Can you post any water test results you have as well? Sometimes that helps pinpoint where a problem started out or what's making it worse.
In the meantime, I'd suggest large daily water changes - in any situation, cleaner water will help your fish to heal.

[the_dougie]

firstly, thanks blinky. normally you're the only one to reply.
I dont have a camera which i can hook up to my computer at the moment. I'll try to get one ASAP.
His fins aren't really frayed, so i guess it's not fin rot. There are little black spots on both pectoral fins now (not many on the second) and in other places theres "blotches" on parts of the edges of them.
He's eating normally, and swimming around normally, but he hasnt built a new bubblenest since my last waterchange (which was 2 days ago. He almost always has one :(). the only other thing is it sometimes seems as if hes searching the gravel for something.

[Blinky]

You're more than welcome, I'm always happy to help if I can. In this case, I don't think I can help much - you've got me stumped!
Try googling 'fish disease symptoms', 'black spot disease', things like that. My fish haven't ever had black spot disease, so I don't know much beyond the fact that it shows up as little black spots on the fish. I believe it's a parasite, like ich. If the fins are deteriorating, it could be bacterial...
You mention that he looks like he's looking for something in the gravel - is he flashing? (rubbing himself with rapid movements, like a giant twitch, against objects) - Fish do this when they're uncomfortable, like when they've got parasites attached to them and they're trying to get rid of them.
*scratching my head*
Take a look online and see what you find, hopefully we can figure this thing out.