I agree that they are challenging to keep and that they are for more experienced reefers. In fact I recently read an article that they are close to becoming considered endangered species because of the aquarium trade (of course I can't find the link to the article right now
). It's a sad thing to watch something that beautiful slowly starve to death in under-sized\non-established tanks.
Anyways, here is some info about them I found on Marine Depot website.
Hopes this helps...
Maximum Size: The Pterosynchiropus splendidus grows up to 2.5 inches.
General Size Specifications: The small size will come to you generally 1 to 1½ inches; the medium generally 1½ to 2½ inches; the large generally 2½ to 4 inches.
Diet: The Pterosynchiropus splendidus is a carnivore and likes to eat mostly copepods in well established tanks. May learn to accept mysis shrimp and flakes with time and patience.
Level of Care: The Green Mandarin Goby is a high maintenance fish.
Behavior: The Green Mandarin Goby may act peacefully toward other fish.
Breeding: Able to breed.
Water Conditions: Keep water quality high (SG 1.020 - 1.025, pH 8.1 - 8.4, Temp. 72 - 78° F).
Range: Indo-Pacific.
General Notes: The Green Mandarin should NOT be kept in anything but a well established Reef tank (6 months or more) of NO LESS than 75 gallons WITH a refugium as it primarily feeds on copepods. Gobies may sometimes attempt to jump out. Prefer presence of substrate. The most colorful of commonly found fish for marine aquarium enthusiasts. Its appetite is not the easiest to satisfy. Commonly called dragonets, which are characterized by elongated bodies, without scales, and also by the presence of two dorsal fins. If purchasing a small specimen it is often easier to teach them to accept prepared foods with patience and work. Will fight with same sex in this species. Sadly, this fish normally dies as it is often purchased and kept in under established tanks without enough food to consume. Death from starvation normally occurs within six months.