This topic is created on the wrong board, scroll down this thread, look at the left down part, you will see
move topic, move it to altcoin discussion.
Do you think tether really has fiat for backing this usdt?

No, tether is completely a virtual currency, it is regulated in a way it will always be stable even if the demand and the supply is increasing or decreasing. Tether has no fiat to back itself but only from the extent of demand.