Most people here strongly
recommend against using live creatures to cycle the tank. The cycling process creates two toxic cycles that the fish have to suffer through. They may very well die from the ordeal.
The raw shrimp method is very effective and IMO
works faster. I used one LARGE JUMBO shrimp in my 46gal and in 1 week I had high levels of ammonia and nitrites. My tank cycled very fast and had the first fish added in about 3 weeks. I put in 2 large damsels because they are hardy and the tank was very immature.
By the way:: any raw, non-marinated shrimp will work fine. 99% of the "fresh" shrimp sold by your local fish market have been pre-frozen whether they admit it or not.
A stable, mature tank is far better for the introduction of fish than a freshly cycled pristine tank with little to no bio-diversity.
If I learned anything about SW
aquariums it is - DON"T RUSH IT, Patients will pay big dividends.
Just my 2 cents