right so i need a good filter for my breeding setup, i have a small tank 1foot x half a foot as a grow out tank, its only temporary. in there i have an airstone and a DIY sponge filter the filter is okay but not up to my standards haha. amoungst my spares i found an interpet pf1 internal filter the intake is around 5 alots at the bottom and they are only around 5mm wide or so. i was woundering will this be okay for my fry if it is on the slowest setting and with the non return valve they have to stop dirty water from being dumped back into the water would this help to stop fry getting sucked up. the fry currently in the tank are 3 swordtails at two weeks old there only around 1-1/2 cm long ? any help would be appreciated !