Gotta say you'll end up with a LOT of cons if you allow the fry to grow up, and then what to do with them! think about what happens next, if you can actually deal with a bunch of cons and not enough space for them all! they breed like rabbits in the right conditions!
you HAVE to keep the filter on, it wont oxygenate the tank or keep it vaguely regulated otherwise, so you can wrap the outside of the filter in thin fitler sponge and tie with non-toxic string, then they wont get sucked up.
i vote letting nature rule, if any survive then good on the parents and the fry for surviving