The big move!

Ok so we have a 90 gallon saltwater and a 10 gallon brackish tank. Recently we have decided to merge the brackish fish into the marine tank, and convert the brackish tank to a QT. All we have in the brackish tank is a small Green Spotted Puffer and a Violet Goby (Dragonfish). Everything I have read says that a GSP will actually thrive in a Marine environment, and that the Goby should do ok also considering how much more space he will have to roam around. We have slowly increased the SG of the brackish tank to 1.025, and both fish are doing fine.

Before we move, I just wanted to check to make sure the GSP won't be nipping at the 2 corals we have. They are a large frogspawn and a Kenya Tree. I have read that those are not corals a GSP normally will nip at, especially if you keep them well fed. I am not worried about the Marine tank fish as all are equally as large or much larger than the GSP.

Has anyone ever moved a GSP from Brackish to Marine, and if so, what were the challenges?

No personal experience with a GSP, but I wouldn't get your hopes up too high about it behavig itself. Puffers are extremely curious fish, and will nip at just about everything. I've been nipped at by puffers while diving, they really aren't concerned with the size of what they're eating. As for corals, not sure. The Kenya might be toxic enough to discourage the puffer.

Your puffer will most likely mess with the corals, good luck with it but be cautious

So considering this frogspawn is literally 10 times the size of the GSP... can he really do that much damage to it? Does a Frogspawn have any stinging / venom defensive mechanisms?

They can do damage depending on the size of the fish but I think the smaller polyps may be more at risk then the bigger stuff.

The corals have stinging cells but more as a defense against other corals then fish.