I have had a green spotted puffer in a 10 gallon brackish(about .008-.010 specific gravity at different times) for about 2 years and just added a wasp fish(Vespicular Depressifons that I finally have accepting frozen food) about 6 months ago and just saved up enough money to get a 55 gallon setup for them. So far I have pool filter sand and about 20lbs of dry base rock in there and about 10 guppies from my breeder tank to get it cycled. I put ceramic media from the 10 gal in the cascade 1000 canister that I got a pretty good deal on. On the bottom tray i have coarse and fine sponge and carbon, the next tray I have fine sponge and seachem matrix(biomedia) and the top layer I have more matrix. I also have a powerhead running in the corner. I know the base rock doesn't really achieve the real "brackish" look but I plan on raising the salinity for the gsp eventually to full saltwater. Does anyone have experience with wasp fish enough to know if they can tolerate a higher salinity? I've heard they are good up to about .016 but im not sure. Also just wanted to see if you guys think this is a pretty good setup.(waiting for a hydor eth 300 inline heater but hasn't shown up yet but tank stays at about 78-80 degrees). Oh my other question is do you guys think that the dead rock will eventually be colonized by anaerobic bacteria or only the aerobic because i have the spray bar from the canister running right over the rock. Also how slow should i raise salinity after the puffer and wasp are settled in? One last question....anyone have any ideas for what to stock this with other than the two fish, the puffer seems to have lost his aggressiveness over the years and wont even touch guppy fry that i put in there for the wasp fish he lets them eat right next to him. Four day weekend i guess i have too much time on my hands thanks for reading guys hehe. Picture is of tank with just guppys think you can see a reflection of my planted tank in the background

I didn't realise you could take the waspfish up to full marine, maybe El_Vulture might have some ideas on that.

As to the base rock question if it is just plain old ocean rock then it is not porous enough to become colonised, youu want REEF BONES which is basically dead live rock.
I don't know your location but plenty of places on line sell it.

Your waspfish will be happier in seawater than anything else, so no problems there.

Cheers, Neale

Neale what Salinity do you think they can cope with? Up to full marine or just a high brackish of around .16?

Full marine (SG 1.025) is fine for them. They are truly euryhaline fish able to adapt the complete range of salinities, though under aquarium conditions at least keeping them in freshwater likely won't work well.

Cheers, Neale

Thanks for the info Neale.
My marine tank has finished cycling so I think I will acclimatise the fish and try them in there )