I am having problems completing an achievement. I do not know what fish I am missing.

If you are trying to complete an achievement that requires catching fish of an specific region (SOuth Korea, US, or Japan) then you need to capture fish that were introduced to the game in the respective region.

You can check the following fish lists for reference:

SOUTH KOREA FISH LIST

US WEST FISH LIST

JAPAN FISH LIST

If you are still struggling to complete your achievement, please contact us through the Support chat in this Help Center.