Need Advice

[corcoadam]

Originally, I put aquarium gravel in the bottom of my tank. Now I've decided to change it and put down sand. I have somewhere around 40 lbs of live rock and two fish in my tank currently. When I put the sand in, I', planning on changing the water while I was at it. When I do all this, I was going to take my fish out so I wont be stressing them out. My question is when I do all this, will my tank have to cycle all over again?
Thanks for any help.

 

[ophiura]

It is hard to know - certainly not guaranteed to happen but there is a big risk as you may remove a hunk of your biological filter.
What fish do you have? Be particularly careful in the weeks after just by feeding lightly and watching your parameters closely.