Adding Fish While Kribensis Have Fry

So my Kribensis pair have had fry for about two weeks now. Prior to that I was thinking of getting some barbs, but held off once I seen that there was babies in the tank.

I went to my LFS and asked them for advice on adding fish, and they said it was probably better if I held off for a bit.

I guess I'm just looking for a second opinion

Thanks,
Billy