Yes, you can use a fish filter. Fish and aquatic turtles are different, but they need the same filtration processes, such as mechanical, biological, and chemical filtration. They may also need oxygenation and aeration as well. A fish filter will work just fine for your turtle, provided it’s the proper size for your tank set up. Fish filters are similar to any other filter that’s catered to reptiles because they can be internal or external, can be power filters, canisters, or sponge filters.
One thing to note is that you can use an under-gravel filter for your turtle, but it’s not recommended. An under-gravel filter is as it sounds - it’s buried underneath the gravel in your fish tank. However, turtles and gravel don’t mix well. Turtles will mistake the gravel for food and eat it. You don’t want your turtle to be eating rocks, of course. So, you can use an under-gravel filter for your turtle without the gravel so that the airflow will come from the bottom of the tank. Just be sure not to place any gravel or sand or anything else of the kind at the bottom of the tank. This way, your turtle won’t mistake non-edible things like food, and nothing will get sucked into the filter that’s not supposed to.