I will agree it does look like a ACF.
Moving it to the 5 g can be very easy.

I would start using some water from one of you other tanks to get the 5 Gal
started. It will have some of the bacteria to help get the cycle started.
and if you can get a small sachet of gravel from the same tank you got the water from
that would be great.
Does the 5 G have a filter?

I would also put a small fish in it like a tetra to help get it cycled.
then you can move it to your other tank.

you would move him like you would a fish.