I think the OP is getting overwhelmed. Too many suggestions. This is what the problem is Fishiekeeper. Your nitrite levels are too high, and all of your fish will die soon if it doesn't get down to .25 or less. But first, I would retest. I don't think your nitrite would jump that high unless you are cycling. Do you know what cycling is? If not, read this:
I just learned about cycling but I already have fish. What now?! - Aquarium Advice
and this:
How to Cycle a Fish Tank - Oscarfishlover.com
Anyway, the best course of action would be to immediately test your water again, following the instructions and doing exactly what they say. By the way, what test kit do you have? Then, if your nitrite is still above .25, then do a water change do get it back down. Basically, if your nitrite is above 10, do 2 80% water changes. If it is between 5 and 10, do 2 70% water changes. If it is between 2 and 5 do 2 60% water changes. And if it is between .5 and 2 do 1 50-75% water change, depending on how high the nitrite is. If you nitrite levels are still >.5 after doing whatever of those steps that applies to you, then do another few water changes to get it down to at least less than .5. Under .25 is preferred, but your fish will be okay in .5 nitrites for a little bit, but try to get them under .25. Basically, when doing a, say, 50% water change on water with 2 ppm of nitrite, then to find out how much will probably be left just do 2*.5. But you should still test afterward.