Is this what a baby koi mouth should look like or is it a stone ?
It smacks his head around a lot and wont eat
- BortLv 62 months ago
I'm not sure it's a Cymothoa exigua that found a home but it's definitely not normal. Usually with Exigua you see their eyes, legs, or butt and I don't see either in the pic even zoomed in. Cymotha are also usually a tan color not clear-ish like whatever that is.
Whatever it is I second Terry's advice that you try to gently pick it out with tweezers or forceps (hemostats).
It's not impossible it accidently and partially swallowed a stone. Fish move stones around foraging for food and re-arranging to make their nest to breed.
Look at your other fish or look at fish on Google. You should be able to see all the way in to their stomach. There is something there blocking food's path to it's throat. Get it out whatever it is.
That's probably why they're shaking, they're trying to get it out.