What Size Heater, And Bacteria In Unfiltered Tank

[ronanphilip]

what watt heater woulld i need in an 18 10 10 tank for a fghter

also as its unfiltered (for now) do beneficial bacteria still live in the gravel? should i add gravel from my established tank or just use new gravel.

 

[ronanphilip]

bump

got the tank and a 50watt heater. put some new gravel in, so is there any point puting some from my other tank in?