Hey Dwarfatize,
This would vary as much as the various places that stomatopods are found. What type are you planning on keeping?
In a recent presentation from Rob Toonen on Temperature and Salinity, he said that the average for the world's reefs where the highest biodiversity of corals and fish are found is 83-84Ã"šÃ‚°F at 35ppt. This is on the high side of what is common for hobbyists, and you might shoot for slightly lower for buffer from our California weather.
Gee... phoenix came all the way to the mantis forum and crashed your thread just to tell you to cook it? As far as I'm concerned, hobbyists keep fish for recreation, and if you happen to get a stomatopod (who live almost everywhere live rock is gathered) and it kills a fish, then it's your fault. Sorry but that's the hard truth.
-Rogue