New tank plans..

Okay!

So next year Im going to upgrade Gonnies 2 footer to a 4 foot! I have a few questions though!

I'm interested on getting him a friend- A male friend- Would this work out (space wise, would there be enough room? How many axies could go in a 4 foot x 18 inch wide tank?)? I'd get an adult if I could, he's about 19.5cm long. His current tank is 2 foot x 10 inch wide.

His tank would be next to my pet mice... Is that okay? I have a tank of girls and they're in a 4 footer too. When I clean them I guess I could move the cage so that no yuckies get into Gonnies water. Would that be okay? Here's my plan-

Bring home tank, wash with water very well (probably hot water, but no soap or detergents or anything!).
Put WELL WASHED 'cichlid' sand on the bottom of the tank.
Fill the tank with tap water and add ACE (water dechlorinator) to the tank.
Place the plants into the tank and surround with large pebbles (so he can't dig them up, the pebbles will be large smooth stones from our birdbath, or ones from the pet shop).
Place filter (Aqua One waterfall filter, I guess medium sized) onto tank and turn on.
Place air stones into tank and turn on pump.
Let run for 3 days.
Do a water test before adding in my fantail goldfish (I actually own them now, they could 'cycle' it for me!)
After a week or two, (doing water tests every 2nd day and recording them), put the fish back into their tank and add Gonzalez + new friend/s to tank. Monitor and do water tests.

How does that sound? Am I missing anything? I'm getting a shelf built into my room so he'd go on that.

Whee this is so exciting!

Might want to put some water from another tank in it. This will help the cycle get going a little faster. Just make shure the water dose not have any sick fish or meds in it. I think you could put 3 in maybe 4 if you had alot of places to hide in. As for the filter I had a water fall. I changed to a fluval plus. You would need the 3 I would think. goes inside you can change the flow if need. I'am not shure about the stones from the bird bath they might have bad stuff on them. I think you should go get new from the pet store. Some one else might know more about stones.