I currently have a 55 gallon freshwater fishtank....?

You know what, in general I would say that saltwater tanks are more care intensive, just because of the extra hardware you should buy, (protein skimmer, more complicated filtration), but I have two examples that would prove contrary to common wisdom.

1. If its your first tank, and its not important to you, try a lightly stocked fish only saltwater tank. My roommate doesn't bother with the fancy lights and protein skimmer needed to keep finicky fish and invertebrates. She keeps two fish (a common clown and a wrasse) in a room temperature tank with an overhead filter rated for a tank 30 gallons more than what she has... and thats it! She has to do less maintenance on her tank than my tropical freshwater, and its been doing great for over a year.

2. My other roommate has the WORKS on his 55 gallon tank: massive protein skimmer, $400 metal halide light combo, three stage filter with reserve tank, and top of the line heaters. Does he have to do more work? Well, he could, but he doesn't check the water chemistry and levels but once a week. So his water looks like crap most of the time and there is nasty string algae all over the tank. The point? NONE of his fish have died from water quality issues.

I guess the point I'm trying to make is don't worry. Fish are hardier than you think and it takes a significant water issue to make the fish die. Just to be safe, either go with lots of fancy filtration with a heavily stocked tank, or keep your tank lightly stocked with hardy fish if you don't want to mess with that stuff.

Well for one, you have to buy the salt or saltwater mix. You have to get a hygrometer and always measure the salt levels. It's messier, too, cause you get salt residue all over the place, especially when the water evaporates. You also can't let evaporation occur too much since this increases the salt concentration. Another thing you will have to buy is a protein skimmer, and depending on what you want in the tank, all sorts of other liquid foods, vitamins, and minerals to add to the water. Also, saltwater fish and organisms are much more delicate and expensive. All of this aside, a saltwater tank is very beautiful and worth it if you do it right and keep it looking nice.

With saltwater, you've got less margin for error than you do with most freshwater fish. Salt content needs to be exact (harder to do than you think), water quality needs to be higher, and you need to run tests not only for the ph, ammonia, nitrite, and nitrate, that you are hopefully doing, but you will need to test for phosphate, alkalinity (buffering), calcium, and magnesium, iodine, and iodide to name a few. Tests depend upon what kind of livestock you keep in the tank.

You'll also need to purchase a GOOD skimmer (most are no good) and purchase all new substrate and live rocks in order to keep the livestock alive and healthy. All this stuff is pretty pricey. I upgraded to a larger reef tank and spent over a thousand dollars - not including the cost of fish- and I had some hookups to get the stuff cheap.

Go to Amazon and check out these two books, to get an idea what you're looking at:

http://www.amazon.com/Conscientious-Marine-Aquaris...

http://www.amazon.com/New-Marine-Aquarium-Step-Ste...

Or go to WetWebMedia.com and read some of the FAQs there.

you have to worry about protein skimming, and uv sterilization too.

Salt water fish require super clean water. And they require much more space than freshwater...

the fish are generally much more expensive as well because they are mostly wild caught... I would deter you from switching to saltwater. A lot of coral and wild fish are destroyed in the pet industry.

if you want plants for the tank ive heard they have to be real and the saltwater fish can cost very much each. thats all i really know

maintaining chem levels: ph, salinity, nitrite, nitrate, alkalinity, temperature, lighting, filtration....