Most Australian short-necked turtle species are omnivorous. This means they eat a combination of plant and animal matter. As with long-necked turtles, they will usually need to be in water to consume food.
Freshwater aquarium plants such as Elodia and Valesneria are two options that are readily eaten and should be provided at all times. It is important to not overfeed the protein meal to your turtle.
Feed a variety of cut-up whole fish such as gudgeons, whitebait, other freshwater feeders, shellfish, mollusks and insects such as crickets and roaches. Juveniles can be fed every 1-2 days to a total amount the size of their head (broken up in smaller pieces) while adults should be fed 1-2 times per week.
Occasionally, you can offer a small quantity of quality frozen turtle food and/or pellet. Appropriately sized live feeder fish can also be introduced into the tank. If food is uneaten leftovers should be removed immediately or alternatively a separate feeding tank can be set up.