I bought an adult male bluefin killifish at Petco. At the time there was a second one in the tank , slightly bigger but without colorful fins. One thing it did have were 2+ off-white round internal things, slightly bigger than it’s eyes. While I want both, I feared an infestation of something. I did buy the male, quarantined him for 10 days. Nothing similar showed up in him. I’ve had him 4 months now. Ironically the other killi is still alive in the tank at Petco. It still looks the same, no better no worse. I’ve tried searching “internal parasites” and all I got was a bit nauseous. Is anyone familiar with this condition? Next time I’m at Petco, I’m gonna snap a pic.