Check the level of privacy offered by different cryptocurrencies.
BTC is public, fully transparent, and pseudonymous. The receiver, sender, and everyone else with access to the public key can see everything about a particular transaction, including the transaction history and balance of funds. Unlike traditional assets, users don't need to provide personal credentials.
Privacy of the Ethereum blockchain, the parent network of Ether, is a work in progress. Although experts are previously leveraging mixing, a technology that scrambles transactions together by introducing a set of fake transactions (called "Mix-ins") plus several real transactions sum to approximate the same number of units of ETH, zero-knowledge proofs is currently studied for Ethereum privacy. The motive of ZKPs is to make the number of funds transferred invisibly, and it allows for privacy by mathematically preventing certain information such as amount, sender, recipient, etc., invisible to the public while still guaranteeing correct transaction execution.
Litecoin is pseudo-anonymous, and everyone can see each wallet's payment history. However, it is possible to "shield" litecoin transaction and thus anonymize it, as long as you can send it to an Incognito address.
DAI is a stablecoin backed by a volatile asset, ETH. Unlike others, it uses smart contracts to maintain its value, and it serves as backing assets to various assets such as UUSD. Backed by DAI, UUSD becomes the first fully anonymous cryptocurrency immune to tools like CipherTrace, used to track transactions. Also, Incognito announced it had anonymized $3.5M DAI.
Ripple, in short, XRP is a native currency of the Ripple Lab designed for cross-border payments. Like Bitcoin, it is pseudo-anonymous except for some measures users may employ.
Tether is completely traceable. Transactions are made to be visible at all times to all parties involved, and to the users from outside. Of course, there are workarounds, such as "shielding" coins using apps. However, transparency is a fundamental quality of Tether due to the fact it under control of a private company that requires your personal details.