fin rot?

Question
I have had my betta for almost a year now and he was well and happy until I
took him to college with me. At home I had hard water, and in college I had
soft water. I use stress coat and bettafix water treatments each time I change
the water. It was colder at college than at home. He developed a blister near
the end of his tail fin. It continued to swell, and appeared transparent, or
milky on the inside. Then more began to appear. I suspected a fungus of
some sort was behind this, and I have been using the Jungle Fungus Clear
water tablets with each water change too. Over the past 4 months I've seen
the fungus clear do nothing to improve my betta's condition- except maybe
slow the process. The blisters have gotten larger and ceased to be
transparent. They are dark now. A few of them have burst, leaving the fin
black and sort of ragged. His once beautiful tail fin is now lumpy with these
blisters that are either entirely black or feature black spots. As another note,
his belly is rather swollen, and has not been excreting waste very often,
nothing has been changed in his feeding amount or schedule. My poor fish is
so sick, and I'm not even sure what to do about it! I've read about fin rot
online, and this doesn't sound a whole lot like it, but I have no idea what else
it could be. Any help would be beneficial! Thanks!

Answer
Hey Jocelyn,  

I think it could be a fungal disease.As you say he has ulcer type lumps, fungal disease normally displays cotton wool ball type lump so this could be what you think are the ulcers. Fish fungus is caused by fungus species such as Saprolegnia. Fungus spores are present in all freshwater aquaria. A disease outbreak is usually a secondary infection of an area of the fish's skin or gill barrier which has been damaged. A Saprolegnia growth looks like cotton wool. It is essential to prevent the fungus spreading deep into the tissue or over the gills. Livebearers are particularly susceptible to fungal problems which can usually be prevented by adding 0.1% (1 gm per litre) of aquarium salt to the tank.

Fungus Treatment

Treatments (such as Interpet's Anti Fungus and Bacteria No.8) stops the fungus spreading and destroys it. The medicine remains active for several days to ensure full healing occurs.

Good Luck!   Jack