He won't live long in a bowl, if he lives a year it'll be a miracle
, so hop on Craigslist and get yourself a tank! Sometimes you can even find one for free if you explain your situation. I found a bunch for a couple bucks that way.
Otherwise perform (small) water changes daily, add a plant to help with O2 levels and feed him a varied diet. (Veggies and pre-soaked pellets.)