...You may also consider adding a second YWG, as they prefer to live in pairs and feel more comfortable to come out with a buddy to watch their back.
What is the likelihood of two YWG getting along vs. aggression? I do not know if you can sex them, but if you added another male to a tank with an established male (like worst case scenario) are you going to be risking a fight?
Several years ago I bought a pair of very small YWGs and a pair of red banded pistol's - they were the only fish in a small tank. They all lived together in the same burrow - it was awesome. I thought I had just gotten really lucky.
Now I have a huge tiger pistol with a rapidly growing YWG and I think it would be neat to have 2 YWGs with this one big tiger, but I would be worried that the establish YWG doesn't really want a roomy. And there is only one place for the burrow, the other rockwork is standing on end and was sawed off to be flush with the glass under a thin layer of sand.
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Sorry for the hijack, but to the OP's question. I think a YWG is far more active with a pistol. I notice that mine like to hang out at different openings depending on the time of the day. I purpose built my rockwork just for the YWG-tiger pair, so I have a good view of them 75% of the time, but left an area where they can't see me and I can't see them, just for the stress factor originally.
Potential downside (as ThRoewer mentioned) is that a tiger is an industrious critter, especially when they get bigger. The one I have is content with his house for 2 or 3 days, and then I come home and it seems that he has moved every grain of sand in the tank. That's an exaggeration, but its amazing what he can do in just a few hours. Like I said its a small tank.
Heck the pistol shrimp are not expensive. And they are among the hardiest critters I've ever kept. I got some TBS gulf live rock and it came with 4 small wild pistols. It took me several weeks to see them all. These guys don't pair with fish. Then I added the tiger and YWG - no issues whatsoever. In fact one of the wild pistols has setup shop within an inch of the big guys burrow.
It's noisy at night, but its just the wild little ones. The big guy never cracks the whip.