Goldfish lump? parasite?

[CrackerboxPalace]

so one of my goldfish has had a black lump inside her for a while, like she’s constipated. The thing is she still eats and swims normally. it’s been like this for at least two weeks and i’m not really sure why. both goldfish eat very well and i’ve fed them both peas twice in the last week. However the black swelling remains. it almost looks like a gravid spot you’d see on a livebearer, though i’m fairly sure that’s impossible.

she also looks slightly emaciated in the mid section of her abdomen.

Parameters are all fine: 0 ammonia, 0 nitrite, 10 nitrate. The tank is 35 gallons, moderately planted and gets a 30-50% water change each week. she’s been with me for a little over a year.

Photos attached

 

[NevermindIgnoreMe]

I can't really tell from the pictures what you are talking about. Could you circle the affected area? You said the black spot is swelling, do you mean light growing in size like an ink blot on paper, or actually swelling like a bruise or inflating balloon?

 

[CrackerboxPalace]

I can't really tell from the pictures what you are talking about. Could you circle the affected area? You said the black spot is swelling, do you mean light growing in size like an ink blot on paper, or actually swelling like a bruise or inflating balloon?

the lump is external. but the black spot is inside the lump and looks like it’s in her digestive tract.