cory off-white mass on back of dorsal, adipose, and anal fin

[xenador]

I have been watching a female bronze cory for some time because I noticed she had a white to off-white mass on the back of her adipose fin. This mass appeared to enlarge when she was ready to lay eggs and in time it would deflate but leave behind a small structure that appeared to be a casing with a yellowish color, and later it would re-enlarge around matting time. In my two months of observation this process has re-occured 2 times and she has had 2 egg laying sessions in that time. She has never had a lack of appetite but is rather shy. I began to get worried when I put 10 of her babies in the same tank with her (55 gallon) and I began seeing signs on them. With the babies the growth seems to be attaching itself on the back sides of their adipose, dorsal, and anal fins. Anyone have any ideas of what this might be, and any possible treatment options? I have included a still shot and a video of one of the more affected babies, along with a couple still shot of the female cory.

note: all parameters normal: pH 7, kH 7 drops, ammonia none, nitrite none, nitrate minimal. Tank would probably fit a description of being moderately planted. Tank mates include 20 tetras, 10 harlequin, 1 dwarf gourami, 5 ammano shrimp, 2 Gardneri Mamfensis Mfuni CSK95-5 fry, 2 cherry shrimp, 10 ghost shrimp, 2 bristlenose plecos, 2 assasin snails, and around 50 malaysian trumpet snails. I feed them 2x a day with flake food, once a day microworms, and black worms. This mass seems to only target the corys.

movie of the baby cory:


still shot of the baby cory:


still shots of the mother cory:



note the white streaks in the photos and in the video are the microworms.