I think the point everyone is trying to make is that 2 GTs or 2 JDs at the size of 2" will not do well for an extended amount oftime in such a very small tank. They will be fine for a couple of months. It all depends on how long it will take you to get their bigger tank. Awhile to you may be two or three months or it could be in a year. This is the major concern, that and being sure that the two pairs you get are compatible and able to live for awhile in a 20 high.