Sabby --
Looks really nice. A creative use of rockwork is something that pays real dividends with brackish water aquaria. Because most plants don't do well, you have problems making the complex habitats pufferfish like. If you watch puffers in the wild, they're often in exactly the sorts of places you've recreated: rocks, rubble, driftwood, and shells.
Arguably, these fish aren't perfectly compatible, since knight gobies for example prefer a lower salinity to that enjoyed most by green puffers. But at an SG 1.010 you should be okay, though I'd suggest varying it a little, upwards and downwards, every week or two. Say, between 1.008 to 1.012, moving one "point" on the scale with each water change. Salinity variations have a very good tonic effect on brackish water fish, and I'd argue are more important than maintaining a constant salinity.
Mind you, Java ferns aren't going to do well above SG 1.005.
Cheers,
Neale
