Emerald crabs and peppermint shrimp

[TheEngineer]

I'm planning to pick up a duo of emerald crabs and a duo of peppermint shrimp this weekend. They're going to stay in QT for 76 days before hitting the DT.

Two questions:

1. My QT is 5g. Is that big enough for the four of them?

2. Seem like the right number for a 50g DT? Need the emeralds for bubble algae and the shrimp for maybe eating an unknown pest.

 

[Zero Nitrates]

That sounds good to me.
My emeralds and peppermint go straight into the tank after a acclimation.