Advice on mixing dragonets?

[Cubeman]

Has anybody got any experience in mixing dragonets? A friend has a male and female psychedelic green mandarin (Synchiropus splendidus) in a 34 gallon tank with lots of rockwork and soft corals. They are the only two fish in there and don't spend any time 'together'. I would like to give him my male spotted mandarin dragonet (Synchiropus picturatus) but are unsure if they will fight. Any advice?