try getting a sponge filter? i think that would be a good solution so the wouldnt get sucked up. they are pretty cheap. the only thing about sponge filters is that you will have to do water changes to clean the tank better (assuming you have a bare bottom tank since its for breeding feeders), and clean the sponge regularly as well.
When I first started this hobby, I had comet goldfish in a 20 gallon tank and guppies in a 10 gallon tank. Guppies have lots of fry but most get eaten by the guppies. I floated some live plants, I forgot what they were called but the were lon and had little leaves, so some of the fry would be able to hide. That's how I kept the amount of guppies in check. Most would be eaten but some of them would survive hiding in the plants, The Doctor