Bronze Cory Fin Loss

[tomchurchman]

240 Ltr tank, using RO, heavily planted.
Ph 6.5
Ammonia 0
Nitrate 5-8ppm
Nitrite 0

6 Bronze corys
1 Sterbai
17 cardinal tetras
2 german blue rams
5 marble hatchetfish

I've had the corys for about 3 months now, and obviously, as they don't come out much in the day, I haven't seen much of them. A few days ago I noticed a small one swimming strangely about in the open, with the lights on. Looking closer he is about half the size of the others, with a very small dorsal and tail and totally non existant pectoral fins. The poor little chap obviously can't swim well and just lays about in the open, I feel bad because I don't know how long he has been like this whilst hiding with the others.
When I got the hatchetfish 2 months ago they developed the dreaded whitespot, which Protozin cleared up within the week, however 2 hatchets died. No other fish were affected and at that point I didn't have the cardinals.
All other fish are very healthy. What could be wrong with the poor chap?

 

[WILDER]

Corys are more prone to bacterial infections.
Does he look to weak to handle a bacterial med.

 

[tomchurchman]

He does have a 'swim' around sometimes, but he must be very weak. He really is very small, no barbels either. I have to say I'd be worried about the other fish if I used any medication. Rams, cardinals and hatchets arent the hardiest of things are they?
Plus I've also got lots of Malaysin trumpet snails and a few Amano shrimp in the tank and I don't think they are too good with some meds either.
How likely is it that the infection could spread?

 

[WILDER]

Bless him he's in a very bad way they can also get bacterial infections in there babels.
Bad news when they lose there barbels as they need them to find food.
What substrate do you have in the tank as sharp edged gravel can wear the barbels down.

Hes not sounding to good the med could finish him off faster so its up to you if you want to medicate the tank.
Bless him.

 

[tomchurchman]

The substrate is sand, and my other 6 Corys are fine, with good barbel growth. I don't really want to risk the medication. He's a tough little bugger to still be going really so I'll let it play out, fingers crossed.
Hopefully this won't spread.
Thanks for your words of advice
Tom

 

[WILDER]

I would still medicate to try and save him.