55 gallon freshwater fish tank

Question
i have a 55 gallon fish tank and i don't know how much water to Chang and what i have to put in water.and how many fish could i fit in a 55 gallon fish tank if all the fish i get are small like 4-5 inches?and how do i treat the water?and if i have to do test when do i do them? and when should i change the water?

Answer
Hi Branden
All of your questions really depend on what types and how many fish you get.   With a 55 gallon tank, there's a wide variety of fish you can get.  You'd be best off figuring out what you want, then asking if they'd be suitable for your tank.  A couple of green spotted puffers that grow to around 5-6 inches is different then a couple of 3-4 inch mollies.  There's just no set answer to give on that.  

For water changes, I usually recommend 25% weekly water changes along with a gravel vacuum, and that's for a normal stocked, fully cycled and filtered tank.  Some fish will require more frequent water changes, like discus, and if a tank is overstocked-which isn't a good idea to do, it'll definitely need more.  

For treating the water, all you need is a good water dechlorinator that removes both chlorine and chloramines-if you're on a public water supply.  That's it.

For tests, I recommend a good liquid dropper test kit that tests ammonia, nitrite, nitrate, and ph.  API Freshwater Master Test Kit is a good one, about 30. at pet stores if you're in the US.  Half that price if you buy it online.  
I would test weekly after the tank is cycled, for  a few months to make sure everything is staying stable.  AFter that, and once you're familiar with everything, at least once a month or so is good to make sure everything is still staying normal.  

Here's a good link to read through before starting up your tank:

http://freshaquarium.about.com/cs/biologicalcycle/a/nitrogencycle.htm

Hope that helps and good luck.  Let me know if you have more questions.

Christy