I moved from 10 gallon to 40, what am I missing?

Hi,

I'm trying to upgrade from 10g to 40g.

I put in live sand from the store as well as half of my live rock from the 10g. Ammonia. Nitrite and Nitrate are all reading 0.

Do I need to cycle it via throwing a dead shrimp in there or am I safe to move the fish since the live rock is already functioning as a filter?