Just to add to this, the artificial colour is added to the fish’s diet. They also adjust the colour depending on the market. For example, apparently Japan prefers a bright pink colour, while Italy and France prefer a less bright pink colour.

This also applies to a lot of subtitling in general. Shows that are in a different language than English are usually first translated into English, and then that file is used as a template for the other languages it’s translated into. It’s easier and cheaper.