Theres still tons of fishies on mid limit games

[imashyboi]

I just had to post this cause it's so funny. I was playing 15/30 today and was getting ripped, I mean literally, I think I had KKs like 4 times and 3 times it lost to a fish who called 2 or 3 bets with a hand like Q5s(45o too!). I remember this guy who made it 3bets to me with a Q5s against my KK and he flopped a flush. For some reason all the loose aggressive players seem to hit flush or 2pair on the river since they call too much. How can players who play on mid limit still make mistakes like this. I checked his WTSD% and it was over 45%, something like 50% actually. Is this too high? I'm guessing 35% should be about right. Also with players who see the river this much should we play tighter alot more and do more traps against them? Just curious what's the best way to attack someone who sees the river this much.

Another funny thing I forgot to add. I raise ATo from the CO and he makes it 3bets to me with a Q2s on the SB, so I call. The flop came something like 7K2r, I check and he bets with his Q2, I check raise. On the turn it came 3, I check again hoping he folds a hand that I can beat. He bets and I check raise him again, he calls. River was a 6, I bet first and he actually called. I thought my play was very strong, I would definitely have made someone folded their duece if he knew what he was doing.