Possible Causes of Unexpected Fish Loss

(in no particluar order)

  1. Windex or other cleaning agents used on or near the aquarium?
  2. Any aerosols used in proximity to aquarium, including air fresheners?
  3. Any pesticides in home, especially near tank?
  4. Any soap, lotion or perfume residue on hands used in fish tank?
  5. Scented candles being burned near tank?
  6. Swings in water temperature or ambient temperature, including possible heater malfunction?
  7. Water level in filter section of tank low, exposing heater to air and causing it to malfunction (see #6) (not to mention rise in salinity)
  8. Aquarium’s power outlet on switch or timer?
  9. Aggression from tank mate(s)?
  10. Water parameters outside of acceptable range?
  11. Fish died without being noticed and left to decay in tank causing ammonia spike?
  12. Defective power-strip, timer or electrical outlet?
  13. Reduced flow.
  14. Is your source water for water changes and top off pure and free of Chlorine and Chloramines? If you’re using municipal water you MUST, at the very least, add water conditioner to neutralize the chlorine.