First off, where are you located?
that would help with trades etc...Crawling68,myself and a few others here are in the San Francisco Bay Area, for instance. You would have no trouble trading him away here.
Unfortunately, most LFS have no interest in the 'ugly' mantis shrimp, as many of them refer to anything that hitch hikes in.
Peacocks, sure, the larger ones, but they seem unwilling to treat mantis as valid pets (And they think that most of us are crazy for doing so...).
Quarter of an inch?
He probably isn't going to kill anything other than pods, unless you have teeny-weeny hermits in there.
Keep him/ they are great to watch as pets.
Set up a tiny tank for him?
Post on a local reef board (Reef central has many for different areas). Someone will no doubt be willing to trade a shrimp, some libe rock, maybe even a coral frag for him. Some folks trae other things, even.
Me, I trade generosity(free drinks and entrance) at my work (Nightclub) for like treatment at an LFS from the manager and another worker.
Good luck.
-Ron
