For the past week now my ammonia levels are rising rapidly. The tank is a 20 gallon and it has been running for almost 2 months now. I have 7 tiger barbs (small) and 1 rainbow shark with 2 live plants. I have stopped feeding for 2 days now and have been doing 20% water changes every other day using Topfin's water conditioner only on the new water going into the tank as well as using API's Ammo Lock every 2 days on the full tank. Despite all of this the ammonia level is still increasing and I am lost for words on what is causing this.