I actually think the "everyone is a secret plant" bit went on longer than intended. The night it was figured out, where they were doing the body body game, felt like the staff was directionless(more than normal) and when it all came out, it really felt to me like it was way late. I also think it was a really good idea.
The issue right now is that I think we are down to as low as 3 actual fish. TJ, Tay, Jimmy and Shinji, with Shinji I can see being a maybe.
Brian is an obvious actor, he was clearly a last minute sub for Frank and I think there is evidence he's friends of Ben. CK is an admitted by staff actor, and you have to be as retarded as TJ to believe that she was brought in to play up drama and Brian was just told to play along.
I've suspected Brian from the start because he was a last minute replacement, so his interaction and "we're gonna get to see banging on Fishtank guyz!!!!!" bait with Trish has seemed fake from the start, and I'm mostly sold on her being a plant too.
Shinji, it's just cause he's a porn actor and I'm only leaning to the possiblity he's a plant cause they are leaning so hard on TJ being the new Main Character after losing Cole, when he's near functionally retarded and extremely tepidly received by the fans. Jimmy obviously is a poor candidate cause he's just waiting for when not if he goes to far, but Shinji is solid and liked. Them focusing on TJ instead of Shinji makes me take suspect he's a plant.
So, we're less than a third of the way through the show, and potentially down to our final two, TJ and Tayleigh(assuming Jimmy is one foot out the door).