Aquarium Ammonia Test Kit. High ammonia levels is one of the biggest and most common killers of fish. Ammonia affects fish by causing the blood to lose its ability to carry oxygen. If you have fish you should be checking routinely for ammonia buildup. This is a simple test kit that can be used for aquariums. If you have fish problems an ammonia test is extremely important. Read about Fish Care and ammonia, click here. If you are unsure about testing or results, please do not hesitate to call us.