Barramundi ponds sit along the coast and on the outskirts of several towns, and they exist because barramundi are farmed here. That means stock in numbers, fish in good condition, and venues that are cheap by the standards of the monster lakes. Stocking and farm licensing are handled by the Thai department of fisheries.
They take lures readily, which makes them the ideal introduction for anyone who finds static fishing dull. A small soft plastic worked slowly along a pond edge will get hit, and hit again, and a beginner can be catching within twenty minutes.
They also jump, shake their heads and throw hooks, so nothing is guaranteed once hooked. That is the useful part of the education: they teach you to keep the rod low and the line tight in a way that a catfish never will.
Sizes are modest, mostly two to six kilos, occasionally much more. Nobody flies in for this. It is what you do on a spare afternoon, or with somebody who is not really a fisherman and needs to catch something to stay interested.
Most ponds will sell you a fish to take away if you want one, and barramundi is very good eating.