I believe the rule is that fish which is 1 inch thick should be simmered for no more than 10 minutes.
What about fish like anchovies, whitebait and sardines which I think are less than an inch thick. How long should they be simmered for in order to avoid overcooking?
What if the anchovies, sardines or whitebait are cooked from frozen(due to perishability), how long should they be simmered for in this case?
Best Answer
As with all fish, just don't cook it any longer than necessary - all you need is long enough to get the temperature up (to 145F/63C), and anything past that is just overcooking. Boiling is a really fast cooking method, and simmering or poaching is not much slower. Note that this also means removing it from the water as soon as it's done, since the water is way above the necessary temperature and will easily overcook seafood even if it's removed from the stove.
Tiny fish like you mention will probably be done in only a minute or two, similar to small. The best way to tell, though, is not to use a timer but to directly check the fish: it should be opaque and flaky. (For small fish, those aren't very big flakes, but you could still pull it apart or bend it and tell.)