Blue bottles are about 1/2" long and are too big for neonates. For fruit flies, with panther hatchlings, I sprinkle some in a red party cup with a little calcium powder in the bottom and swirl it around. Once they are lightly dusted they cant climb the cup as easily. I usualy sprinkle some around in the baby bin and make sure they are not getting stressed out from the flies crawling all over them. Feed as many as they can eat in 5-10 minutes a couple times a day. You will be able to gauge how many you should put in with them after the first couple of times. Should be the same with newly hatched veilds.