I agree. My guess would be this Procambarus Clarkii. They are a very common crayfish. As the name implies they are usually red when adults and from the southern swamps, however they now live over a lot of the USA and the rest of the world (in some places they are considered invasive pest). Chances are if you have ever eaten crayfish you have eaten one of these. To my knowledge they are the only commercially farmed crawdads in the US and are shipped all over the world.
As far as diet, don't put too much energy in thinking about it. If it is organic they will probably eat it. complete garbage disposals, veggies, plants, any meat, smaller relatives. Even to the point that they will eat some of your slower/smaller tank mates if they can catch them, assuming you have tank mates.
That said they also need a little cover if they are in your aquarium with more aggressive players. My convict and jack dempsey would torment relentlessly any of the crawdads I put in their aquarium.
