in order to farm the moonlight aether sand need a fisher leveled to access spearfishing and have access to thavnir area. you will be catching gilled topknot. it will be a medium fast fish. its honestly the easiest way to get these sands in my opinion. no rotation needed no teleporting no timed nodes.
source
Is it lv90 aethersand?
Are there any stats that help you get better collectability on spearfishing?
Spearfishing is so good now. Im happy that they made it useable for everything scrips and sands.
Another great way to tell is the size of the square on the fish.
Cant wait pick back up gathering moonlight aethersand I spent my time leveling Fisher to 90 starting at 80.