First of all, note that tether is not ethereum. Tether (or USDT) is a token that has been issued on many blockchains.
One of the blockchains in which you can make a USDT transaction is ethereum.

All USDT transactions that are made on ethereum blockchain can be seen on any ethereum explorer.
https://etherscan.io/token/0xdac17f958d2ee523a2206206994597c13d831ec7