Hi there...My tank just arrived today. I noticed a silicon smell inside, when i asked the delivery guy he said it hasn't been washed. My questin is, how do i wash it or will it be fine if i cycled it for about 5-6 weeks ???

congrats on your new tank.

as for washing it out or not i personally do wash everything i get for my fish including the tanks when they arrive. as i use is a vinegar and water solution and make sure to rinse it well then let it air dry. i feel better knowing that i removed any dust or other type of particles from the tank before i set it up.

x2, let the fun begin!
Keep us posted!
btw, my tanks never "just arrive", I have to do some heavy lifting myself, but I like the idea.
Good luck and enjoy your aquascaping.

How meny fish do i need to cycle a 135 G and what kind of fish are best for this job ???

It depends on how many fish you are going to add. Get a goldfish for every fish you are going to add and about the same size. Example use 2 1inch goldfish if you are going to add 2 1inch oscars