The babies are still too small to swallow BW since their mouth and stomach are very small and not yet strong to feed on BW. Therefore their system also can process it (daphnia) faster. It will take them quit longtime to finish chewing/feeding and process the BW compared to the daphnia.

It's like feeding solid food to human baby..cannot what coz their body & digestion system is not fully develop yet.

But it is good to start teaching them to take the BW also. If I don't have the daphnia, just cut the BW into small/short pcs to help the feeding it.

Once they r comfortable with BW then can forget about the daphnia. I think in few weeks time they will be ok with just BW and small pellet (eg. saki-hikari)

Cheers,