emergence of three other species, which sprang out of the butterfly like Russian dolls.

That was a good read thanks mate. Now all I can think of is a chest buster coming out of a chest buster and then another chest buster comes out of that one and cant stop laughing at the absurdity of knowing Xzibit did this.

https://en.wikipedia.org/wiki/Ceratothoa_oestroides

Geographically given where I am, it’s probably this one

Oh wow, the first one sounds mean. Never heard of an isopod parasite (but I'd now guess there are many more aquatic ones?). And inducing necrosis of the tongue to be the new fish's organ, ouch :O

And what a wild ride the second story is! Thanks for sharing :)

Finland

I did not expect this.

Also in the archipelago, which I live close to. Usually there sorts of stories are from Australia.

Seems like a similar species is common where I am.

https://en.wikipedia.org/wiki/Ceratothoa_oestroides

Horrifying. Thanks for the link, although to be honest I probably could have googled “fish tongue parasite isopod” at some point in the past decade+.

Interesting that the Wikipedia page has photos that wouldn’t have rang the bell for me, the one I remember was exactly like the one in the post.

Edit: the article describes a habitat that is pretty far from me, this was in Lebanon in the eastern Mediterranean over a decade ago. Could be a similar species.