I have never seen a Mandarin 'fight' for food. Their own way of searching for food is slow and easy. They will look over a pod for seconds, then nip. The do not tend to socialize with other fish, except perhaps a mate they have spawned with.
Yes frozen brine are better. They have added nutrients & vitamins. You might even try some Formula 1 or 2 pellet food. They've been known to eat that also.
He/she will love the pods
. By the way, is it male or female?