In article .com,
says...
Tiny fry have appeared. I have only Goldfish. What keeps the little
guys from being sucked into the filter?..


My pump has never been a problem with sucking in fry, it would though if
they got near to it. My fry stay in the plants which are placed at the
opposite end of the pond to the pump/filter. I would expect the other
fish would have eaten fry long before they got to the pump.