whats up with my severum

[Bigtdotcom]

i just got home from a 2 week holidays and noticed something strange on my sev, to me it looks like a cut thats a bit infected? whilst i was away i had a friend doing water changes and my flatmates were feeding my fish for me. From what i have been told it has been there over a week, i was also told that my sev and choc had a bit of a fight while i was away and i also noticed a few scales mixed up in the gravel while i was doing a water change.

here is a quick video

http://youtu.be/QEXs5vosCGg

 

[hamfist]

I think your assessment sounds about right. I'd want to treat the fish with a general anti-fungal, anti-external bacteria type treatment. I've no idea what's available in AUS so won't make any recommendations.
Maybe even isolate the fish, but only if it doesn't start to resolve with the initial treatment as, no doubt, it would be quite stressful to the fish just isolating it to start with.