All Dragonets are not equal when it comes to ease of feeding.Your Scooter Blenny is a Dragonet just like Mandarins. And as far as feeding Mandarins it depends on the species you're talking about. Synchiropus splendidus, the Green or Blue Mandarin will normally need a healthy population of pods since they rarely eat frozen. S. picturatus, the Spotted Mandarin on the other hand almost always take frozen Mysis with very little training. S. stellatus, your Red Scooter is more like a splendidus and will probably need a lifetime supply of pods. Your common Scooter, S. ocellatus is the easiest of them all to get to take prepared foods. As far as aggression Amphi is right, as long as you're talking different species the odds of a problem are remote. If you want to be 100% sure of avoiding aggression determine the sex of your Scooter and if it's male get a female Mandarin. If it's a female it won't matter. They're easy to sex, just look at the anterior dorsal fin. Males will have an extension of one of the spines.