The LFS here sells Ghost Shrimp - 12 cents a piece.

My Puffers love them. Since I have caves and a number of hiding places
for my Gobies, some of the Ghost Shrimp have reached a size where they
are no longer intimidated by the Puffers. The Puffers swim by them,
eyeing them, but no attempt is made to munch them.

Since my Knight Gobies, who share the caves with the Ghost Shrimp, stay
so fat, I think this may be due to the Ghost Shrimp's off spring.

Anyway, I explained this to my friend who has a 55 Gallon African
Cichlid Tank. He now reports his Cichlids won't even give any of the
Ghost Shrimp time to hide before making a meal of them!

One more thing I should mention....
My Oscar Tank has no top cover or light.
(They didn't like it. I was just glad I was home and heard the noise
before they were cut or electrocuted)
A lot of the Ghost Shrimp I put in the Oscar Tank decided their chances
were better on the living room floor. :-)