Bullied Angelfish

Tank size: 31 UK Gallons (37 US Gallons)
pH: Neutral
ammonia: Unknown
nitrite: normal
nitrate: normal
kH:
gH:
tank temp: 26-27 degrees (normal)

I have in my tank, 2 angelfish, 1 pearl gourami and 1 dwarf gourami, 2 small clown catfish and 1 orange sailfin.
One of my angelfish is being bullied and most of it's right pectoral fin has been torn/bitten away. Its anal fin is also browning and looks torn. I have treated the tank for finrot, to no avail. This has happened quite suddenly, and after observation, I have only seen the dwarf gourami nibbling at the dangling remains of the fin. Is it the gouramis that are bullying my angel?
If so, is it possible to divide the tank with the gouramis on their own, and how much space would you allow for the gouramis, they are both quite small.

The brown on the fin does it look fluffy looking.

http/www.nippyfish.net/flexibacter.html

The brown isn't fluffy at all, it looks like the fin is dying because of the rips. I have no pictures, but i'll attach an illustration.

Hi there, I asked the same question about Angels sharing a tank with Gourami on another thread:
Angel fish and Gourami sharing a tank
Hope that puts your mind at rest and is of interest?

(nice pic of the angel fish by the way )

You will need a bacterial med then, just keep an eye on signs of flicking and rubbing, good luck.