Yeah during the Cycle the ammonia will rise alot then start to go down and you will then see Nitrite and then see nitrates, Eventually the ammonia and the nitrite will go all the way down and you will just have nitrates. Thats when your done with the cycle and then do a water change.
On another note. I know you see all those fresh water fish in fresh water tnaks. They usually recomment 1 fish per Gallon in freshwater and 1 fish per 10 gallons in Saltwater. Look at it this way and it really does make sence. Fresh water fish live in dirtyer water Hence a smaller volume of water ( River Lake ), Salt water fish live in the bigegest water volume there is ( The oCean ) So ofcourse you cant compare the two. So When you add fish do take it very slow. Trust me i experienced this when i first started and lost aver 250$ in fish. I know its not alot but it was to me lol. There are some exeptions to the rule like fish size and all that but just take your time and alwys test your water. I test 2 to 3 times a week.