If you add tol2 transposase to a fish already carrying Tol2 elements, you will mobilize those Tol2 elements. See for example, Urasaki et al, 2008, in which they used this property to mobilize Tol2 elements and induce mutations upon incomplete excision.

Normally, if you want to introduce a second transgene on top of a Tol2-generated transgenic line, the Tol1 system can be used (see Koga et al, 2008). Another way would be to use a meganuclease such as Isce1 to linearize the new transgenic plasmid, which can often then integrate into the genome. See Soroldoni et al 2009, or Thermes et al., 2002, for examples.