Pink maomao have picked up the nickname of the ‘suicide fish’, as they will often slowly sink as you get closer, drawing you deeper and deeper.
When hunting them your approach needs to be calm with no fast movements. A longer gun of 120cm + is best as this will give you better range. Using reef structures to hide behind also works well. Once the fish know you are targetting them they will generally go deeper and out of your safe diving range.
It is therefore better to approach them from the sea-ward side as you can often herd them quietly and carefully into the rocks which will also prevent them from going deeper.