About 1/4 inch. Let's just say, I haven't even had the cuttles two weeks (12 days) and I have had to place two orders for mysids (one for 250 and another for 200...), and I will be placing another order tomorrow. I did order my second batch from aquaculturestore.com and I used priority shipping (instead of overnight). The little guys arrived in two days and were fine... I may place an order with shrimpstuff.com in hopes that if they ate bigger shrimp, they wouldn't have to eat so often...