The smaller size and softer bodies of the lobstersmake these ideally suited for most pets. We typically send a mixed colony of sizes ranging from a fraction of an inch up to adults of approximately 1 1/4".  When deciding how many to start with you need to consider what animal you have to feed. Lobster roaches are very prolific breeders, so even if you start with a small group, they will make a good-sized colony in just a few months if you let them. Many people ask to start their own colony and have good success starting with a mixed sizes order to begin with. To house my colony I use large Rubbermaid tubs as my main containers. Place several egg carton  upright in the tub, being sure not to let them settle into each other.  A paper food dish is easy to use and replace every so often.