I was wondering if anyone knew if this is normal for leathers and polyps. I have had my tank for almost 3 months. I noticed recently that the water smelled kind of fishy or like dead shellfish. I can't find any dead animals. I tested my parameters: salinity 1.023, pH 8.2, Ammonia 0 ppm, Nitrite 0 ppm, Nitrate 20 ppm. I was worried so I did a 20% water change. The yellow fiji and green star polyp haven't been open for 4 days now. Should I be worried?