Lots of good fish sellers at aquabid. Yes the overnight shipping is a major cost after you have already set the price for the fish. As an example, you might get 4 or 5 pairs of endlers for $20 but the shipping at the wrong time of year could easily cost another $30. That would usually be overnight with a heat pack. If you can go to the right time of year, you don't need the heat pack and can allow express shipping instead. That would reduce the shipping cost to maybe $15.