LCS do not do well in a cage. Been there done that very unsuccessfully.
I've watched LCS in an aquarium, and, not surprisingly for a "sucker", they're extremely bottom oriented. Last year, I had some in a 2x2x2ft screen cage with a solid bottom, which I covered with gravel--they overwintered fine in TN, although I don't think they grew at all over the winter. After watching them feed and on and relate themselves to the bottom in an aquarium, I can imagine that they would do very poorly in a floating cage with a mesh bottom.
They'll do fine in a 20 gallon long aquarium. They really like shrimp pellets and algae wafers. They're very active and fun to watch as they pick though the bottom sand and gravel.
