Food for your preds

[Hart1985]

There are many parasites that over winter (go inert) in winter from northern climates, so are able to reawaken when thawed.
Even simple parasitic disease causing parasites, Ich and Lernaea, and bacteria such as columnaris, that can survive inert in a smudge of frozen mud.

When feeding salt water fish is it only best to feed white fish?
More darker fish like mackerel to oily?
I could stack a freezer in the summer with mackerel for feed and have a bit of fun as well