Well sure; you normally put some kind of filter on the intake or around the whole pump that has holes (or whatever) that are smaller than the fish or anything else the pump might damage or be damaged by. Actually, I don't even think my pump's outer cage design has holes that small (I do have baby fish on occasion), but the cage probably keeps fish away from the pump suction. A fine filter directly on or around the intake often get clogged up too easily which really suggests a bigger cage is a better idea. A common solution, if the pump is small enough, is to place two of those pond plant baskets around it. They have fine holes. you could also use other dollar store plastic baskets of one sort or another.

Those are good suggestions, thank you! ;)

also put some lava rocks in side the plant basket,keeps the pump from clogging up too fast

Thanks. I think the fantails were to small, but the koi may have been sick, thus he couldn"t save him self.