You ever try tong feeding? Never thought about tong feeding a fish but works with snakes and reptiles. Could splash a food item around on the water surface, or even touch her right on the lips with it if that may trigger a bite. Just make sure to hold the tongs perpendicular to her angle of approach so she doesn't get jabbed straight on with them if she happens to strike. Other than that maybe trying to replicate what she'd eat in nature, which is all kinds of odd things from bugs to fruit and nuts as I understand. Maybe offer her a pinky :P Fascinating creatures.
This is the last pair I bought. Nice and long and only $10 for 2 https://www.amazon.com/gp/product/B097DBVTH2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1