Flavor – How to remove bitter flavor from lime rind in soup

Fresh seafood shouldn't be overly "fishy". It's generally older seafood that will get a stronger "fishy" smell and flavour.

That said, there are 3 approaches to a "less fishy" result:

1. Absorb/reduce fishiness: you can always try something like soaking it in milk (which you can then save to use for a fishy bechamel when your sister isn't dining with you). You could then rinse it off and cook it however you want. This should help "absorb" some of the fishiness and make it milder.
2. Disguise fishiness: The other angle is to "cover up" the flavour with lots of spicy glaze or garlic/lemon flavours instead.
3. Pick mild seafood: The other thing to try is to pick a more mildly flavoured fish (e.g. a white fish instead of something like tuna or salmon). Avoid oily fish as they tend to have a stronger flavour. Choosing something really fresh also falls into this category.

Green peppers are green because they are unripe. Unripe fruits and vegetables are naturally more bitter and less sweet than ripe ones. By far the easiest/laziest path is to just use a red pepper. It's essentially the same food, just ripe.

Sugar won't really do anything to the bitterness other than mask it. Salt will. Khymos has written that in parts of Asia, unripe fruit is commonly eaten with salt, salty spices, or soy sauce. These are all excellent options for peppers, as they reduce the bitterness and enhance the taste.

Finally, cook at low heat if possible. Pan-fried peppers tend to be a fair shake bitterer than slow-grilled or oven-roasted peppers.

(P.S. Removing the skin obviously works as well - I personally prefer them unskinned, but if you want to skin them, have a look at this Chow video on it - it's simple to do, you just char the outside and shake it in a plastic bag.)

Also, the interior white part and skin (not the big obvious part, but the sort of interior skin of it) are rather bitter also. Remove it be sliding your knife carefully and parallel to your cutting board slowly and shallowly.