This simple, fresh salsa brings a bit of zing to lovely grilled fish like red snapper, sardines or mackerel. Perhaps my favourite fish, mackerel is super cheap, but it needs to be really fresh for cooking.This simple, fresh salsa brings a bit of zing to lovely grilled fish like red snapper, sardines or mackerel. Perhaps my favourite fish, mackerel is super cheap, but it needs to be really fresh for cooking.