No good! lol I just moved my hatchling corns from the hatchling 6qt tubs to my AP econo rack with 1753 setrilite 15qt tubs. the smallest of which is 12 grams. well he discovered that the gap is bigger than he is. lol I found him after only 20 minutes of searching. I love my AP rack so please dont think i'm knocking them. if you are using them make sure that the babies are big enough not to get out.