I have a fifty five gallon fresh water tank with community fish in it. I woke up this morning and my balta sharks were dead alont with all neons and variuos other fish. I went to the pet store to check the water and nitraes and ammonia were only slightly high nothign out of the norm. I found my themonter was broken and I never noticed it before. I have lost about 20 fish and only have a bout six left anyone have any idea's on how to save teh rest. or what is wrong with the tank! I did put new plants in five days ago could that have been the downfall?