Blenny & Gobie quantity?

[OutsideBrian]

How many blenny / gobies would be acceptable in my tank?
I currently have a twin spot blenny and a black clown goby.
I was thinking of adding 2-3 more of different types. One being a yellow watchman, possibly a linear and or a tailspot.
I currently have a blue damsel and a cleaner shrimp.

 

[nereefpat]

Tank size? By counting the egg crate spaces I'm getting about 30" long?

 

[OutsideBrian]

It’s 36” by 18 x 20, 57 gallons

 

[DH78]

In my 120 I have a Lawnmower Blenny and a Watchmen Goby (with pistol shrimp). The Lawnmower goes after the Watchmen whenever it tries to move more than 6" from the home it shares with the pistol shrimp. It might have been because they were not added at the same time, but the Lawnmower is aggressive towards fish of similar shapes. The Goby postures at every fish in my tank, but doesn't actually go after them. Aggression between them could be a problem if they can't carve out there own little spots in the tank.

 

[OutsideBrian]

Anyone else have thoughts, experience?