There are 2 species of Lima, elongatus and Lima. The elongatus are much rarer and only grow to 12 inches while the Lima will grow to a 2 feet. Personally I would put the elongatus in a 125 gallon and the Lima in a 180 gallon.
so for the 29g I wanna do bumblebee catfish, if thats a good tank size how many should I do? if not should I put them in the 50? if so how many in there and what should I put in the 29?