I send my USDT from poloniex to bittrex, but I fill BTC wallet 
Can I recover it??
Can I recover it??
Here is Bittrex cross-chain recovery policy.
https://support.bittrex.com/hc/en-us/articles/115000961172-Bittrex-s-Crosschain-Recovery-Policy
If your deposit was worth less than $5000, than consider it a lesson learned.