Remove the new filter's media and put as much of your mature media in. You can cut the sponge to fit. You don't replace filter sponge, just swish it in old tank water when clogged, saving all good bacteria. If you transfer all your mature media you can add your fish.
Thanks for that confirmation, Noah. I can't understand why it's never struck me before. If sponges never need replacing, why do companies such as BiOrb say to replace them every so often?
Sounds great. May do that actually, then get the heater up and running (to heat it up for him) and pop him in once the temperature has come up in the new tank, does that sound reasonable?
Was all done a couple of hours ago now, and he's still exploring away after being added just short of an hour ago. Thanks for all the advice - it's greatly appriciated
I'm thinking of just him and some shrimp in the tank, do you agree? Which shrimp might be best? Sorry for all these questions...