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.

[xenador]

update: after unsuccessfully dosing with Marcyn I, Maracyn II, and Maroxy and spending ~$100 on those treatments I started to give up, figuring it was probably something that was genetic and nothing to worry about.

I added some marbled hatchets to the tank to get some more fish to hang out in the upper sector of the water column. However that species of fish is evidently very sensitive to light changes and so my timer kept them freaking out for hours at a time(5xs a day).

All the new activity scared all of the other residents and put everyone on edge. As time progressed I noticed an outbreak of ich so I got rid of the hatchets and began treatment. after the first day of treatment with the tetra ich guard I saw a little improvement in the white fluffy spots. After around 4 days of treatment with the ich medicine I am seeing noticeable decline of the spots (on the older specimens it has disappeared completely and on the younger guys it has "deflated" to half their size).

[imma24]

Glad to hear it sounds like you got the ick under control.

Do you have a quarantine tank? It usually helps when you get new fish to watch them for any diseases and treat it separately before adding to your main tank. I myself acquired a 5gal for that purpose after a new fish I put into my tank came down with ick - I had to treat for a while and couldn't add any new fish for a whilel.

[KatzeSlaugen]

My females do the same thing. IIRC i read that weather/dojo loaches get the same type of "blobs".read that it was a buildup / storage of fats.
whatever it is mine get them off and on and have been for close to two years and have never lost any of them so i wouldnt worry about it too much.

+1 to a quarantine tank and ide recommend not doing with meds like that without knowing what the ailment is. it can possibly lead to other problems in the tank