It is Not normal. You don't have enough nitrifying bacteria. Anytime you set up a new tank you have to go through a bacteria cycle. You one start with a few fish as to get the cycle going. After a period on 2-6 weeks, this cycle will end and you slowly fill your tank with fish. You should try using Cycle or Stress zyme. they both are bacteria in a bottle. monitor your Ammo and Nit levels and eventually they should fall. Also make sure you have enough biological media in your filter for these bacteria to grow on. never wash this media in chloronated water. Alot of people come into my store with Ammo problems and they tell me they washed their bio media because it looked dirty.