input: [0] Poor Water Quality [2] Rapid gill movements, inflamed gills, excess mucus on skin, fins clamped to sides, lying on bottom, rapid deaths of multiple fish [4] Test water quality frequently; conduct periodic water changes; ensure good aeration and filtration of the aquarium water. [3] 
output: Test water and conduct a 25% water change. If no improvement occurs, use an ammonia remover, aquarium salt or an appropriate water- quality-improvement product.