Yep, until they hatch to fry... was why I asked if Timmy was going to pump from the tank they were in.... much more likely the fry would be sucked into the pump IMHO....
Secondly yabbies and marron generally prefer still, low flow water..... presumably if you're pumping out Timmy you'd be returning water back to the tank at some stage....
The inflow of water might dislodge the eggs.... would probably disturb the yabbies anyway...
May be don't pump from that tank directly... maybe join to another tank, som that it's tidal...
