Since I've bought this game I've managed to catch almost all species of fish no problem (well, with enough perseverance). Mekong Catfish however, seem to avoid me like the plague. Used rigs from various forums and spent 13h at this venue (more than all others combined) and have caught 174 fish (71 redtails) but have yet to even hook/see a Mekong. Is my game just broken?
No, definitely one of the more allusive catches there. Size 2 hook, boilies such as Monster Red and fish the margins, shallow, especially the right side of the lake worked well for me. Not really sure about best times but Sunrise is always a good bet. Good tactic is when you see them appear in the shallows, cast to them if you can. They're not a regular catch, so patience wading through the other species is important.
The large boilies on #2 hooks catch about 75% of the bosses in the lake. As Chizzckh said when you see a boss fish near you cast all of your lines near and it will usually take them.
I'm not trying to catch any boss fish, I just want to catch any Mekong. And I've never even seen one in the water either
Use one of the pegs just to the right of the bridge, and use the throwing stick to throw a large amount of boiles right at your feet. The fish will start to come, at first will be carp and pacu, but after a minute mekong will start to show up. Try sunrise or at night.