Small, medium and large available. this listing is specifically for a 50 count pack of small mealworms. It is recommended to keep mealworms in the fridge so that they do not grow in size they go into hibernation. If you would like your mealworms to grow in size you can leave them out they will grow it is recommended to give them a wet paper towel weekly for hydration if you decide to leave them outside the fridge. Please message us if you have any other questions on how to care for mealworms!