Transferring puffer to new tank

[zookey]

I have read on here in many different posts that very large water changes can stress out the fish by changing water chemistry greatly. My question then is .... if you are transferring a fish to a new/larger tank that is set up, do you also transfer all the water from the preexisting tank along with the fish to keep the water chemistry as close to "normal" as possible? Or do you just set up the tank with all fresh water matching the salinity and transfer the fish into the new tank?

[Blaine]

I would say transfer as much of the water /substrate, etc as possible from the old tank as well as any filters, etc. This will maintain the biological filter and should keep you from having to re-cycle the new tank. Monitor the Ammonia, Nitrite, and Nitrate levels closely after the switch and do water changes as necessary to keep the levels in check.

[Pufferpunk]

If you have been doing 50% weekly water changes (as you should be), then your water is pretty close to tap water anyway. If you're upgrading, then fill the new tank 1/2 way with the old water & the rest with fresh water & then it's exactly like a 50% WC.

[zookey]

Okay.... I actually do two water changes a week of not quite 50% since his tank is smaller than it should be. Cleaner the water the better for him in a tight tank while waiting for his upgrade. I had ordered the rock for his new tank but it still has not arrived so am going to do the transfer this weekend. Just didn't want to shock him badly in the process.

Thank you both!