They have aquarium salt, its not the same as marine salt though. Some even say table salt (the kind we eat) is alright to use, but some disagree. Anyway, it says these puffers DONT NEED any salt. And says best health is in pure freshwater.
Wow, I'm glad you found that link--there is sooooo much bad info on the internet. Don't go with the 1st few guys who post an answer. Ask them how long they kept a DP in BW? Mine only lasted 2 days, before I knew any better.
For more onfo: http://www.**************.com/forum...rinotetraodon-travancoricus-the-dwarf-puffer/
I think the tank looks fine. But I'd clear out one of those big rocks for more swimming space and just add a few more plants. Also that bamboo isnt a real aquatic plant and will rot eventually, and will cause problems to your water quality.