Pla tu actually refers to a type of short mackerel that is native to Southeast Asia. You can often find frozen pla tu in Asian grocery stores, and I’d recommend seeking them out because they have a unique flavor profile and texture.
Pla tu are smaller than the mackerel we are used to in Western countries. I snapped the below pic while making some nam prik pla tu in my home in Chiang Mai, Thailand to show you what they look like.
Packing: 30X290 G.