do not add anything in the tank if the tank itself has a minimal amount of bacteria.
A fish... no. A crab... no. A snail... no.
Would you ever want to live in a house that has no walls, no heat, no bathroom?
No. Will it keep you warm and dry? No. Because it would not be an ideal environment for living. The same concept applies for any livestock. Putting them in a tank where there is no bacteria, would be like rehoming a lobster in a pot.
And Master Shake... no offense but how do you not figure that bacteria is not on a dead shrimp? Ever gotten diarrhea from poorly cooked food? That's because airborne bacteria start colonizing on food. This is why it is essential to thoroughly cook food.
Why does a shrimp assist in colonizing bacteria? Because 1 it's from the ocean, even thought you purchase it from supermarket, its laid on ice and out of water moisture from within and any residual water that is trapped within the shrimp itself will come out and start to feed on that shrimp.