so i want a crayfish but the biggest aquarium i have to put one in right now is a 5 gallon. i know a little one inch baby will be fine in there for a while but are there any species of crays (that are not hard to find for sale) that will be ok in a 5 gallon as an adult? what about those generic brown/reddish crays sold for a few dollars as feeders? how big do those typically get?