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old tank syndrome

  1. Possible Old Tank Syndrome, fish swimming at top

    Freshwater and Tropical Fish
    I believe I have experienced Old Tank Syndrome. I noticed my platy and one danio swimming in the top corner several days ago, checked the water parameters, and the ammonia was at 0.25ppm. I immediately added Prime to the tank, and did a ~30% water change. The ammonia remained down over the...