Possible New tank just for Hillstream Loaches

[buddythelion]

Hey everyone, I might get a used tank that is 18 1/2" high, 20" long, and 10" wide. About how many Hillstream Loaches (preferably the 'sucker' kinds) will live happily in this size of tank? I would like to add some sewellia lineolata in this tank but am afraid of overcrowding. Oh, and there might be about 6 danio chopraes in case I need dithers.