Jambo! Mr. Nature here, with the odd mata-mata turtle from South America, which occasionally shows up in the pet trade. Years ago, they had one at Noah’s Ark Pet Shop in East Lansing, but it wasn’t for sale. The shop’s owner had a lot of animals not for sale: he found it hard to part with them.
How does the mata-mata snap up fish so fast (and he never misses)? When he suddenly opens his large mouth, water rushes in so hard that the nearest fish gets washed in with it. I can’t think of any other animal that does this.
Note: I no longer keep pets that require live food. My painted turtle did just fine, sharing my suppers–and that’s how I wound up with a tankful of pet crickets. To me, goldfish are pets and nice companions, not turtle food.