it's part of cycling. all the bacteria are trying to find a home so in a while, they'll either go to your filter or your gravel! just wait a couple of days and it'll all be gone!
if it's the 40gallon tank on ur sig, i think one or 2 guppies wouldn't hurt if u want them a lot. do a water test, and if any of the parameters are off, don't do the guppies, it'll only hurt the process. if the water if cloudy but the tests come out ok, a couple of guppies should be ok. i know how it feels to have a really cool tank but not be able to put fish in it, i had to organize my room before my mom let me put fish in it!