Thanks! I'm going to try and get some white light video for better visibility, realizing the blues are making it harder to see what's in there.Assuming its a parasite which we don't know for sure, here are the possible outcomes if you leave it in there and not take proactive steps
1) It might overwhelm and kill your CBB.
2) It will make babies and infect your whole tank.
3) It might just die off on its own.
4) The CBB will survive but with the impairment and increased respiration.
At least do the clove oil method to get a closer look at the fish gill in your hands. With a magnifying glass so we know what we are dealing with.
Faced with similar outcomes, I chose to get it off of my fish as per my post above. The diagnoses was done by the vet, although I had to do the procedure. The cost was too high.
Take the CBB and put it into a QT. Maybe observe him for a while. If you can observe it closer in this isolated QT, try some praziquantel liquid form first. Don't use it in the main tank. Bad for some inverts. https://www.liveaquaria.com/product...-dYnLQabQI8sHXfnGMwDD09reTnk4CNwaAnhyEALw_wcB
Before I decided to attempt to be a fish surgeon and tried the clove oil method, I first tried prazipro , but the worm wouldn't budge. Not sure if it the medicine worked and just in a deathgrip or stuck, but it was still clinging to the inside of the gill and his tail was still protruding past the gill cover. Except for the differences in the fact that I don't see a long tail coming out of your CBB's gill compared to my red arowana, they both exhibited a bulge in the gill, meaning that something is in there. Might be some parasitical isopod? I've seen some in fish's gills and some on bodies of fish through the years and they definitely cause a large bump and won't let the gill collapse totally when respiring if it was lodged in there.
Then in the same QT tank. I did the procedure. After sedation, I took forceps and gently lifted the gill and pulled the worm from as far to its head as I could and it came off.
Here is an example of a parasitic isopod in a fish gill: I don't think yours is that big, if it even IS an isopod.
This is assuming its a parasite in the first place! But there seems to be a foreign body in that right side gill. The sedation is completely harmless to the fish. Good luck Dr Biff!
Heck, it might not even be a parasite. It might be like this kid shoving up lego blocks up his nose. https://www.bbc.com/news/newsbeat-53819306