Planning a 30g Green Spotted Puffer tank.

For a tank that size only one GSP could live successfully. Bear in mind that they are aggressive and typical tankmates are other GSPs, but in a bigger tank.

Adult GSPs are fully marine so you need to balance the SG with your tank decorations. I almost went for GSPs but decided on a figure eight instead.

What I was going to do was use aragonite sand and lots of base rock. Something like reef bones. Not live rock at this stage unless you get hold of a GSP that has already been acclimated to SW. For low end brackish you could keep java fern, jungle val, bacopa and water sprite since they do ok. As salinity gets above 1.006 (roughly) these plants will stress out and should be pulled. I think trying FW plants is really more of a hassle for this fish, since they will only be temporary and there is the risk of pollution from dead roots and leaves.

As the puffer gets older and you raise the salinity you start getting options for SW plants, or macroalgae. I've managed to keep hamileda at an SG of 1.017 but any lower and it starts dying off. The only plant I know that will survive the transition is mangroves. On the full marine stage there is a wide range of really nice macroalgaes. You could also try a few easy corals such as mushrooms and ricordia.

Hope this helps. Good luck.

Figure 8 puffers are OK with BB gobies from what I've read. I was thinking of doing a figure8 puffer, 2 knight gobies in a 29 gallon BW tank. Im pretty sure you can only keep one bb gobie at a time though, I think I read that somewhere, but it could be a conditional thing.

bb gobies will be good tanke mates to try

"Although often sold as a freshwater or brackish water fish, this species requires full saltwater conditions as an adult to really thrive. They should only be introduced to a fully cycled aquarium matching the salinity they were being kept in previously. The salinity should slowly be raised to at least 1.015, preferably full marine conditions. (no more than .002 SG per week"

i found this here so you can trust it http://www.pufferlist.com/puffer/brackpuff.php?puffid=15

GEPs will definately eat BBGs. I'd forget about tank mates, until your puffer is in SW. There are no tank mates tough enough or that can follow a GSP into SW. In a large enough tank, w/tons of decor, you could keep a few damselfish or a tomato clown (no delicate "Nemos" for a GSP!).

See: http://www.thepufferforum.com/articles/puffer/introtogsp.html