36”? For a 30l? Are you sure it’s definitely a 3’ tank??
How tall is the tank - If it’s very shallow you need a lid more than anything. As for wrasse, maybe a Lubbock’s fairy (Dependant on how aggressive the one you get is - I highly doubt it’s going to be aggressive though), Pink streak wrasse or any of the possum wrasse.
Other wrasse include:
- Halichoeres Iridis (Only if it is a true 3’ tank, I would say by the end of it these need no less than 48” of swimroom)
- Cirrhilabrus naokoae
Honestly, a lot of the smaller wrasse that stay around 3” at max size will fit - avoid flashers, after watching them dart in the LFS I highly doubt one would be alright in a 3’ tank.