Can you add a Cory catfish to a red ear sliders tank to help keep the tank clean?

Adding a Cory catfish to a red-eared slider's tank is generally not advisable. Red-eared sliders are omnivorous and may see smaller fish, including Cory catfish, as potential food. Additionally, the water conditions and habitat needs of these species differ significantly, which could lead to stress or health issues for the catfish. It's best to keep them in separate environments that cater to their specific needs.