Yes you will still get a cycle so you are a few weeks out from a fish just yet . It is a good idea as mentioned to use lr to help cycle the tank and to also filter the tank ......... I also failed to say that when you rinse you filter sponge do so in old tank water after a water change I rinse mine in the sink but soak it 20 minutes give or take afew in old water from the tank to dilute the tap water ....Tim Mantis shrimps do stay fairly small however they are in my opinion a bit dangerous in that they do bite as well as hard ....they can also shatter a tank if they want to ......JMHHO :mrgreen: