Cory With Whisker Rot

[InaneCathode]

I've had these two cories for about a year and a half or so. Everything is grand until a couple days ago i noticed one cories whiskers are starting to shorten and his fins are just barely starting to etch away. Last time this happened with a cory (3 times actually) they died within 2 weeks as their fins eroded away. How can i tell if this is a bacterial fin rot or fungal. I'd hope its fungal as i dont want to nuke my filter, and as the tank is very stable.
Ammonia 0
Nitrite 0
Nitrate 20ish

10 gallon with a betta and one other cory (some bamboo shrimp too but, meh)

Help?

 

[shang hi]

10 gall to small for corys realy, they can live in there but they arer happyer in a 20gall. what gravel so you have because the barbles (whiskers) can get damaged easly.
if it is bacterial, repair your filter by using mature media from another mature tank, or use the link in "new to the hobby" - "members willing to donate mature media to newbys" (its pinned) and see if someone would be willing to donate some mature media after the medication is inished. or use a hospital tank.....

 

[Underwurlde]

Some anti-bacterial meds don't actually effect the bacteria in the filters. I have tried Maracyn in the past, so I speak from experience: It worked well and the filter did not crash.

Andy

 

[InaneCathode]

I've used maracyn 1+2 in the goldfish tank before and within 3 days it nuked the filter. Nothing unmanageable but kinda a pita to do water changes every day.
I'll wait-n-see with the whisker rot whilst using melafix, if it gets any worse he'll go in the hospital tank with maracyn 1+2 and an antifungal.