New betta with growth on gill?

[Xiuhcoati]

Hi everybody,

My husband and I went to Petsmart, as we do most fridays, to view the new shipments they have. The fish ladies know us quite well there, and one of them asked us to look at a betta they had with an unusual condition. The betta, pictured below, has a lump on its gill that they've been unable to treat.

Petsmart rules allow them to only treat with "Betta Max" and, concerned for the betta's welfare, they asked if we'd be willing to adopt it so we can give it the medications it needs.

I've got a wide selection of medications on hand, but I'm not quite sure what it is. Symptoms include curling fin tips (It's labeled as a double halfmoon tail) and the large lump on its gill. Really, it looks like the fin edges are from self mutilating. It's just a guess though.

I am not sure what it is, so I put him in my hospital tank, used gloves to handle him, and am currently boiling the net I moved him with. Can someone take a look at this lump and make a suggestion as to what could be wrong?

Here are pictures, I'll fill out the form in a moment to the best of my ability.

[Xiuhcoati]

Housing
What size is your tank? Moved him from cup to 1/2 gallon hospital tank
What temperature is your tank? 80 degrees, using a small portion of repticord to keep it warm
Does your tank have a filter? No
Does your tank have an air stone or other type of aeration? no
Is your tank heated? yes
What tank mates does your betta fish live with? none - he's sick!

Food
What type of food do you feed your betta fish? haven't fed him yet. Normally pellets
How often do you feed your betta fish? once a day

Maintenance
How often do you perform a water change? bi-weekly
What percentage of the water do you change when you perform a water change? complete water change
What type of additives do you add to the water when you perform a water change? Prime

Water Parameters:
Have you tested your water? If so, what are the following parameters?

Ammonia: 0ppm
Nitrite: 0ppm
Nitrate: 0ppm
pH: 7.0
Hardness: unknown
Alkalinity: unknown

Symptoms and Treatment
How has your betta fish's appearance changed? got him with this lump
How has your betta fish's behavior changed? just got him
When did you start noticing the symptoms? when petstore clerk dragged me over to see sick betta
Have you started treating your fish? If so, how? I changed his water, put a small amount of aquarium salt in, and am debating meracyn 2
Does your fish have any history of being ill? yes...he came this way :P
How old is your fish (approximately) looks about 8-9 months, but thats just eyeballing him.

[Xiuhcoati]

Forgot to add: I have a 10 gal to transfer him into, but I am concerned about fish tb. I am okay with throwing out a half gal I got god knows where, but not an entire aquarium