I do not normally use a breeder net/trap. I did actually purchase one last week when Nicky the black swordtail gave birth as I didn't have any place to put her babies. I used it for about 4 hours and then went and bought another 10 gallon tank. I think they are way to small for a swordtail to use as a birthing area, I wouldn't put any of my females in one for even 5 minutes, they'd freak out. I usually either move my pregnant ladies to a 10 gallon tank or let them have them in the main tank. The nice part of putting them in the 10 gallon is that once labor is done, the mother can be moved out and the fry can grow up in the 10 gallon, beats the heck out of chasing fry all over a large tank. I'm now up to 4 10 gallon tanks for quarentine, maternity wards and recovery wards.