I now have all small tanks, 10gal or less for Bettas and would like a shoal (6-12?) of Tiger Barbs in a new tank but space is an issue. Would a 20gal long suffice for them alone, with maybe some Cory's or Oto's? Since so much importance is given to surface area, is a 29 gal much better as both the 20gal and 29gal have the same footprint, the 29 just being taller (and heavier)? Their 30" length is about the maximum I can wedge in my den. Should I just stick with species with smaller requirements?