Mandarin and Scooter Dragonets
Personality
Mandarin: dull or bland, in the same meaning. It's not a pet, but rather a domesticated grazing animal. The image of overweight gazelle comes to mind, the movements are really graceful. Paying no attention to the keeper, other than moving to the back, to check the farther rocks for something new.
Having another dragonet fish, eating in Mandarin Diner, seems to give them a hint that this is food. But they are always trying to enter the glass through the wall, not an opening, and having a hard time with this.
Scooter: This has a distinctive personality, the fearless little terrier, recognizing keeper, coming forward to feed, taking comfort of keeper's presence in new hostile surroundings (being new in a big tank with another scooter) for starting to eat, just as it was in a small personal safe tank. Much faster and clever, than mandarins. I have the impression, that they are living in much faster passing time - like mice in comparison to the rats, may be because of that they are faster to wean on a frozen or pellet diet.
Personal preferences: Red scooters.
Behavior
Both spend most of their time, checking rocks for food, mandarins - paying no attention to anything else in the world, 
scooters - aware of surroundings, climbing the rocks and claiming the pole, observing everything from the top of the world. This is the one-eyed scooter, healed well.
Conclusion: Having the same sex same species fish in even a big tank (90g in my case), is not what I wish you to experience ever.
Compatibility
Mine are ignored by other fish in 90g tank: mombassa lionfish, tassled filefish, valentini puffer, blue-green chromises and 4-striped damsel. Percula clown, when is not busy, sometimes hangs around to see, what the mandarin is doing. This gave the opportunity to make a colorfulness comparison.
In 10g tank for two refugee fish: smallest chromis with arrested development (you know the type - youngster, not growing for months, even with abundance of the food) and the weaker scooter, the chromis swims above the scooter sometimes and watches, what it is doing. During the feeding, chromis tried to eat all the food, so nothing drops to the bottom for a scooter (ha!). After this chromis started to grow fast and become a totally normal adult.
Reef safe, will not bother corals, but any small crustaceans, fitting its mouth, will be eaten (copepods, amphypods, isopods) and may be something else, growing on the rock, because all LR grazers come to nibble on a new piece of LR from refugium.
Safe with bigger crustaceans: porcelain crab, hermit crabs, and a blood shrimp. Mandarin was cleaned by the blood shrimp (or fire shrimp), as anybody else in the tank, but very rarely and months later.
Next page: Feeding