for midas, the aquarium foot print must be large, nothing under 18" wide is ok, 18" wide is minimum, that is why 75 gallon tanks lend them self perfectly, they are very common in the foot print of 48"x18"x21, if you wanted to keep it in a smaller tank it would just be cruel, 50 gal breeders come in 18" wide but 3' long is not enough, 4' long minimum, in my opinion, i wouldn't do midas in anything under 125 gallons. at the sizes the fish are at in your case, the divided 125 will be okay, but when larger they will need more space