Growth on fin with red dots

[cynster]

The second day I had my fish, I noticed this with my bigger fish, but it looked like he had been injured and cut his fin. I added some stress coat, the dosage for an injured fish. Eventually it looked swollen and I thought it was just trying to heal. Now I see it on his other side and on some other fish too. The best example of this not being a normal growth of the fish is that one of my largest has the growth on her left side but not her right side.

I change the water every other day, 50%, they get varied foods, the water looks clean, the fish are active, they all eat and dart around, but I am noticing the ones with the growth are shaking once in awhile as if something itches, and they'll rub against things in the tank.

I'm using MelaFix by API which contains Melaleuca 1.0% supposed to treat open red sores, fin and tail rot, eye cloud, pop eye, body slime, mouth fungus, and open body wounds.

I was told by the pet shop people to use this because it's very natural and it still works to keep the fish healthy.

I'm curious as to what these things are, so I drew a picture of what the growth looks like at various stages and what the fin should look like. Does anyone know what this is?

 

[cynster]

Could find an edit post button, sorry for the double post.
These are pictures of the fish and the growth on their fins. It's hard to see, but you can see it right behind the dark coloring on their gills.

 

[cynster]

Just got back from the fish store where I bought them. They've never seen this disease before (I showed them pictures and described it) but they think it might be a parasite. They recommended a clout treatment, so I've bought a quarantine tank and they have had their first clout treatment today.

Treatment has started on the 5th day after seeing the first sign and incorrectly diagnosing it as an injury. Fish have been in the aquarium with clean water, stable PH, and still act like normal fish other than itching at their fins and rubbing against the ground/fixtures.

If you know what this is, could you let me know? I will update on the treatment and their progress.

 

[cynster]

Additional Details:
Tank Size: 29 Gallons (the 6 have now been moved to a 10 gallon quarantine)
Water Parameters: 7.6 PH (stable), hard water, 40ppm Nitrate, 0 ammonia, nitrite .25ppm (used API solutions) and I know my tap water is hard
Freshwater
Aquarium has been set up for 2.5 years
# of Fish: 8 : 6 FM, 1 JD (5"), 1 unknown cichlid, possibly discus (4") : JD for 1 year, the rest are 7 days
The fish were not placed under quarantine, but I took care to buy at healthy pet stores
Temperature: 78F
Plants: At first, no, but I've introduced some recently - after the disease had occurred
Filter: Marineland Penguin 200B
Other equipment: a bubble blower
Sunlight, somewhat direct. There is a window nearby, but not too much shines in.
Feeding: 3 times a day, small portions.
Unusual signs: growth and scratching. Growth has red dots.
Treatment ahead of diagnosis: stress coat when I thought it was an injury.

Went through the diseases, and it doesn't sound like any of them.

 

[Pomatomus]

I can't really see what you mean from those pictures. Are you sure it isn't inflammed lymphocystis?

 

[cynster]

It's the pink area right behind the black coloring on the gills (which is a normal color marking) It's like the armpit of the fin for lack of a term for that area. It's not fuzzy (even though the picture looks fuzzy). It's very hard to see, but it isn't as lumpy as lymphocystis and what is odd is it is occurring on the same area of each fish, where lymphocystis seems pretty random looking to me Also, the Lymphocystis doesn't seem to show the red dots, possibly burst blood cells? Thanks for your input though. I think that's the closest disease to what it is.

Also an update: 5 hours after 1st treatment of Clout medication, infection isn't receding, nor do I see anymore growth, but the growth was very gradual; for all I know it may still be growing.