Seting up a new freshwater aquarium

Question
Hi! I just bought a new 5 gallon complete tank setup at a local petstore. It came w/ a filter w/ biowheel & filter cartridge, hood & light. Today we just added the rock gravel & two live plants. We also bought at the petstore a rock that came from a well established aquarium that has moss growing all over it and after treating the water w/ declorinator we put everything into the tank. The tank is up & running now w/ one male betta in it. We have had him for a few days now, but he was in a small bowl prior to being put into this tank.

My question is: The rock w/ moss from the well established aquarium...will that help or hinder the cycle process? Should we not have put it in there and should we have put the one fish in there too? I've read up a lot on setting up an aquarium and I understand the whole cycle process and how everything works, but I wasn't sure if I made the right choices here. Also, is it a must to have a heater in the water even though the tank is kept inside where the temp is regulated at about 75F? My husband doesn't think we need one.

And...I've been reading so many conflicting opinions, but should 25% of the water be changed once a week, even during the cycle process? Just don't vacuum the gravel until the cycle is complete? Should I add another hardy fish to help the cycle move along better?

Thanks for any answers you can give me!

Answer
Adding the rock with the moss will not hurt anything, your tank will still cycle but with the addtion from an established tank you will actually be helping the process along. With your current tank temprature you really do not need a heater, if it drops below 70 F then you will want to add a heater to keep it consistantly at 70 or above. Don't add any fish until after the cycle process and make sure the fish you do add are going to want the temp at about what your tank is at, this will just make things easier for you. With a five gallon the water chemistry will need to be monitored as they typically do not balance themselves. With the filter you have you really shouldn't need to do the maintenance every week, at most every two weeks. With a smaller tank you will want to take out less as well, only about 10%, to much water being taken out will really mess with your water chemistry once the water has cycled, you don't want to cause the tank to start the cycling process all over again, when to much water is removed this can occur. Also, with the water changes its good to add a product called aquasafe, basically this neutralizes the water for you and lessons the stress on your fish, a dual action product really. Wait about a week and have your water tested, if things are close to where they should be you can consider adding one or two fish at most. If the water chemistry is all weird your tank is still cycling and you will want to wait until this normals out.You will want to have tank tested for ammonnia, nitrate, nitrite, and pH. Best of luck and happy fish keeping, if there is anything more I can help with please let me know.