Please have a look at the pix below. I've caught a few Hybrid Bluegill that have these bumps along the edges of their fins. Any idea what this is, and what may be causing it?

thanks
[Linked Image from forums.pondboss.com]

Attached Images
1a.jpg
.20 acre pond-that leaks/4-5' deep. Stocked 6/22/19 with 300 BG(supposed to be HBG, removed 100+/- so far), 100 RES, 3carp. On 8/20 added 300 HBG, + 21 5"HSB. 8/21 added 5 8" SMB, one 10" LMB , one 14" CC