Prefilters

[SweetApples]

Would this item protect dwarf aquatic frogs from being sucked into a canister filter:

Amazon.com: Eheim Accessories Pre-Filter Module: Pet Supplies

[Mentat]

Depends on how strong is suction (filter flow). I've used this one ( Amazon.com: Pre-Filter Sponge 3 Pack for Fluval Edge Aquarium: Pet Supplies ) on Aqua Clear power filters to protect cichlid fry and works great. Only thing is, you have to rinse (in tank water) during weekly water change or it clogs out and slows flow. Good luck !