what media is inside the filters? All filters, even built in ones, should have some mechanical filtration (pad, sponge, etc) and some biological filtration (surface area for bacteria to grow-usually plastic balls, ceramic rings, etc)
What you need to do is transfer some of this from the established tank, to the new tank. It should be pretty easy to either cut a piece of sponge or take some of the bio media, and put it in the new tank's filter.
What you need to do is transfer some of this from the established tank, to the new tank. It should be pretty easy to either cut a piece of sponge or take some of the bio media, and put it in the new tank's filter.