in the swim
Doing the same things that other people are doing; following the fashion (as in business or social affairs); busy with what most people are doing.
Jim found some college friends at the lake that summer, and soon was in the swim of things.
Mary went to New York with introductions to writers and artists, and that winter she was quite in the swim.
out of the swim
Not doing what others are doing; not active in business or social affairs.
Mary had to stay home and take care of Mother while she was sick, and soon felt out of the swim.
The toy manufacturer who is out of the swim will lose money.
sink or swim
To succeed or fail by your own efforts, without help or interference from anyone else; fail if you don't work hard to succeed.
When Joe was fourteen, his parents died, and he was left by himself to sink or swim.
Tom's new job was confusing and no one had time to help him learn, so he had to sink or swim.
swim against the current
swim against the stream
To do the opposite of what most people want to do; go against the way things are happening; struggle upstream.
The boy who tries to succeed today without an education is swimming against the stream.