shld i use live rock during cycling?

[Shinguuji]

shld i use live rock during cycling? my nitrite is still quite high, i recently spotted a pincer sticking out of the rock, i think there's a crab in the rock, but my nitrite has been super high(more than 20ppm?) and yet the crab is still alive? is it advisable to let the crab stay in there? or will it die and decompose, skyrocketting the nitrites?

[Shinguuji]

furthermore, more nitrite has been REALLY high for very long....maybe 20ppm???? for abt a week already....is this normal, my nitrite went up pretty fast, only abt 4days after setting up the tank...i'm using cycling bacteria BTW