What parasite or thing is this?

With wings, possibly a fungus gnat of sort, perhaps a fly. A close look would reveal 6 legs.

More likely just a nuisance tank pest, but you might closely examine your turtle with a magnifying glas for tiny worm looking critters, Those could be one of the parasitic fly larvae.

Ridding these often means sterilizing the tank and everything in it. Procedures for such can be found in many keeping forums.

Gnats and flies are often introduced with foods put in the tank. Their larvae can be so small as to being overlooked.

It's an aquatic beetle larva. I'm not going to guess at which one.

Did you mean "infested"? Because "ingested" means "ate". And they clearly didn't eat your turtle's tank, right.