Aquariums and Audio Equipment

Salt? You mean from splashing? Certainly evaporation that boosts humidity can be a good thing in the winter months, and siad vapor is indeed salt-free, so it's ok.
If you put the tank at least a few feet behind the speaker plane you won't damage the imaging too much.
I sit in an 8' nearfield triangle two feet in front of my Steinway (angled back to help with non-perpendicular lines), and the stage is 20' deep!).
DO keep the lights and pump on the OTHER AC leg....but what about the gurgling? And don't you listen with your eyes closed? Maybe fish ARE fun? Hmmm....I'll stick to the Steinway.

I have had reef aquariums for 15 years and marine fish for ten prior to that. The issues I have had in those years are two. First noise, I would have a hard time with the noise in my present 400 gal. reef. The sump is in the basement and the tank above it but the overflow still makes a rushing noise. I have thought about a mini reef in my music room, possible circulating through the main tank but have not figured it out yet. The electrical noise is hardly an issue if you have dedicated circuits, I have the pump and metal halides on the other side of the panel to keep them as separate as possible. The other issue I had was about twenty two years ago, my wife and I were making a water change. The 55 gal. tank was between two rooms and up high. Or TV was below and in front. The bucket I used to pour the water into the tank slipped and about a gal. of salt water went into the TV. Damn tune just never worked the same after that. After three years it died, I opened it up to find a green aged copper look, very nice.
I think if it's well thought out a tank would be awesome! I don't know if you could do this but if there was a room on the other side of the wall, the entire tank could be set in that room with a cut-out for the tank. It would be very easy then to control the noise and would not effect the depth of the sound stage.
And yes Clueless, I have about 70 corals in mine. If you think Audio is expensive, you have not tried marine aquariums. Some Red Sea fish can run close to $1000 and corals can cost close to that for healthy specimens. It's a real drag when those babies die, try selling a dead Red Sea Angle over the Internet, maybe we need to start ReefgoN and the beginners can buy the old timers dead stuff.

The other issue in addition to the others mentioned, is the vibrations that you will place on the fish... I had a similar setup at one time, and usually the next day after a listening session there were dead fish (from them killing each other). Moved the aquarium to a different room and never had another problem... Guess it depends on how sensitive / aggressive the fish are... I had triggers and more aggressive species.. I think the risk of a leaking aquarium is minimal, assuming you have well maintained equipment that is less than 10 years old, continuously in operation from the purchase... But you can never tell when 80 gallons will wind up in the room. The issue with evaporation and salt is minimal... Usually, the salt will stay in the aquarium, and I noticed no issues from that with the equipment... Anyone who lives anywhere near the ocean has more to worry about than what your aquarium could produce...

Weird, in various setups I have never had a problem with vibrations affecting the health of the fish.

Always thought I would but never did.

Jadem6- yea, finally found a hobby I could spend more on then fish. On the plus side audio gear usually does not just up and disappear....quit eating, get sick, melt, kill other audio gear, chase other gear out of the room...

An 80g tank really is not that large of a tank. Depending on the filtration setup, the tank could be setup very quietly. With larger tanks anytime you move thousands of gallons per hour, things can get noisy.

We have a 110 Gallon marine tank on the back wall of the listening room... all of the filters are in the basement and the only sound from the tank is that of rushing water (which is actually quite soothing). The tank actually helps to break up reflection off of the rear wall since it is an imposing structure with numerous angles, shapes, and materials.

As far as disturbing the fish, keep in mind that sound is magnified under water so what might be 95 db to us might be a heck of a lot louder to the fish. We haven't seen a fish die from a loud thwack of a bass drum though. One problem that we do have is that the plexiglass is showing very small superficial cracks from the loud sound levels (at least according to the aquarium people). Their suggestion is to replace it with a glass tank (which we didn't do in the first place because of the unconventional stand it is on and they said plexiglass would work better).

As was mentioned earlier, saltwater aquariums are an eternal money pit and when you see a $1000 worth of fish floating at the top of the tank, you kick yourself for not buying more audio equipment instead of the fish. Oh well, but it looks nice...