problem with another female golden killie - strange tail growth

[xyyz]

i already had one female golden killie succumb to dropsy about a month back. now i noticed another problem when i got back from my 4th vacation.

this female golden killie has a strange growth on it's caudal fin. it's this sorta white growth that is present on both sides of the fin. while it seems a little like a cotton tuft, it's a bit more dense. the fish is pretty trusting and friendly, so it allowed me to take hold of it's fin gentlely. i put a small amount of pressure to try and remove it, but it's anchored in there pretty well.

the fish is active and has a healthy appetite. it's also still pretty social.

i'm including some photos. maybe someone can tell me if it's some sort of fungus or something else, and what i outta do to treat the condition successfully.

[xyyz]

two more pictures

[Zagz]

What size tank and what are the parameters and other tankmates? Depending on tankmates, I would dose the tank with pimafix as a precaution. Also have you seen the fish's poo lately?

[xyyz]

here are the params:

size - 29 gallon
tankmates - 4 golden killies (including this one), 1 opaline gourami, 4 silver angelfish, 1 discus
temp - 78-82F
pH - 6.2-6.4
nitrites - very close to 0 (FINALLY!)
ammonia - total NH4/NH3 ~ 1ppm, but according to the seachem indicator, less than .01ppm is NH3

i started the precautionary mela/pimaflix last night. i also noticed one of the silver angelfish had what appears to be an injury around the dorsal fins. it started to produce some slime on the tips of the dorsal spines. at least i hope it's an injury and not fin rot.

i haven't seen the killies poo, if you're concerned about the large abdomen, but she's always had a big abdomen. what should i be looking for in the poo?

is it wise to try and scrape the growth off? although it does appear to be growing through the caudal fin.

[xyyz]

does either melafix or pimaflix have anesthetizing properties? right after i dose the tank, the fish seem to become really sluggish - they look like they're high.

[xyyz]

no comments or suggestions?