Hi,
I always loved the golden headed sleeper goby. Yes they swim and dump sand as they go, but that isn't the real problem.
The 30g tank isn't large enough, the sleeper goby gets too large for that size tank. They feed on the fauna in the sand. Once that fauna is gone, if they have not learned eat frozen, they die of starvation. the act of sifting the sand is how they feed, and trying to keep them alive without that fauna, is near impossible. Not to mention you need the fauna in the sand to keep the tank properly balanced.
If you need your sand cleaned and stirred up, try some nassarius snails. They won't deplete the fauna in the sandbed, and they do keep the sand stirred up, which helps to keep it clean.