Critical

Sudden Fish Mortality

When several fish die within hours, the cause is almost always a rapid shift in a lethal parameter — oxygen, ammonia, pH, or temperature. A systematic diagnostic approach using multiparameter testing is essential to stop the loss and prevent recurrence.

Symptoms & Signs

  • Multiple deaths within 24–48 hours
  • Fish congregating near inflows or aerators
  • Gills appear pale or bleeding

Common Causes

  • Acute ammonia spike from overfeeding or filter crash
  • Rapid pH swing from runoff or chemical addition
  • Thermal shock from sudden water changes

Species & Temperature Context

Water-quality parameters vary significantly by species, water temperature, production system, and local regulations. The ranges shown throughout this site are general guides based on common aquaculture species (tilapia, catfish, shrimp, trout). Always verify parameters for your specific species with a local aquaculture extension service or research institution before making management decisions.

Top Products for This Problem

Check Price
AMMONIA-KIT-DELUXE0.0–8.0 mg/L TANColor chart comparisonN/A (colorimetric reagent kit)N/A (lab kit)$Check Price
MULTIPARAMETER-PRO-900pH 0–14; DO 0–20 mg/L; Cond 0–200 mS/cm; Temp −5–80°CMulti-point auto-recognition per parameterIntegrated quad-sensor probe headIP67 (handheld), IP68 (probe)$$$Check Price