fairy wrasses can go in 20's mandarins realistically can't as there is no way to sustain a copepode population and would be unrealistic to keep adding copepods
I would respectfully disagree. Most wrasses in the Cirrhilabrus/Paracheilinus genus require at least 50 gallons.
Pseudocheilinops ataenia or a possum wrasse would both be a great choice. They don’t require nearly as much space and are easy to get onto prepared foods.
Barnacle blennies are comical to watch and perfectly suited for a nano tank.