Largest fan following during season 1 for multiple reasons, including creepy guys, and then has streamed consistently with a few breaks ever since. Season 1 was different because everyone was really excited to learn more about the fish outside of the show so there was a lot of hype around "What will they do next?!" with everyone. Only Josie has persisted from that. I'm sure a lot of current watchers have simply worked her streams into their routines at this point.
Vance was the second most successful streamer outside of season 1 and I think didn't stop until he worked on season 2. Letty streamed sporadically and had an abysmal start which probably demotivated her but then she found her footing with the Ice Poseidon & Friends.
Oh yeah everyone thought she was Japanese at first so all the weebs latched onto her immediately. The season 1 video quality was bad.