Well first off, I don't think there's too many people willing to say "Here is a dwarf Fahaka from Lake Turkana that you can put it in a 30G tank". As you have read in another thread there is no scientific data for it but there are many owners coming forward with these cases only to find about them later. I'm sure that some of them are stunted indeed, but if know what you're looking for you can tell whether or not it's been disfigured or not.
I suggest you look to the puffer forum - search keywords such as "Turkana", "Dwarf Fahaka", etc and you shall see more answers.
The messiness of the Fahaka, dwarf or not, would need more than just 30G. If you have a 30G tank you'd be better off looking for something else other than take your chances on something that potentially needs much bigger.