Observables might have a default Scheduler they operate on that is different than the one the RealmObject was created on. Accessing Realm objects on the wrong thread will throw an IllegalStateException.

RealmObjects are live objects that automatically stay up to date. Operators that expect immutable objects will most likely not work as expected, e.g. distinctUntilChanged.

Retrofit 1.x automatically uses a worker thread.

Use the Realm async API instead of subscribeOn to move Realm work off the UI thread.

You can use Realm.copyFromRealm to make a copy of Realm data.