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Tricaine / MS-222 Dosing Calculator

Calculate MS-222 working solutions for zebrafish sedation, anesthesia, and euthanasia. Computes powder and stock dilution recipes with sodium bicarbonate buffering.

ZebrafishAnesthesiaClient-Side
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Load example MS-222 Dosing data to see the full workflow

Configuration

Recommended: 100–200 mg/L

Dilute from stock solution
  • Preparing MS-222 working solutions for zebrafish sedation, anesthesia, or euthanasia
  • Calculating stock solution dilutions for specific experimental volumes
  • Determining sodium bicarbonate buffer amounts for pH neutralization
  • Preparing anesthetic solutions for larvae vs. adult zebrafish

Don't use for

  • As a substitute for IACUC-approved protocols — always follow your institutional SOP
  • For non-aquatic species — MS-222 dosing differs for amphibians and other taxa
  • For determining anesthesia depth — monitor fish behavior directly

MS-222 Pharmacology in Zebrafish

Tricaine methanesulfonate (ethyl 3-aminobenzoate methanesulfonate, MS-222, Tricaine-S, TMS) is the most widely used anesthetic for zebrafish and other aquatic vertebrates. It acts by blocking voltage-gated sodium channels in neurons, producing reversible loss of sensation and motor function.

Stages of anesthesia in zebrafish: - Stage I (light sedation): Reduced reaction to stimuli, normal opercular rate - Stage II (deep sedation): Decreased opercular rate, reduced equilibrium - Stage III (surgical anesthesia): Loss of equilibrium, no response to tail pinch, slow opercular movement - Stage IV (medullary collapse): Cessation of opercular movement — euthanasia threshold

Recovery is achieved by transferring fish to fresh system water. Recovery time depends on concentration, exposure duration, and water temperature.

Safety and Regulatory Notes

MS-222 is a DEA-exempt substance but is regulated for use in food fish (21-day withdrawal period per FDA). For zebrafish research, the primary regulatory considerations are:

  • IACUC approval is required for all anesthesia and euthanasia protocols
  • pH buffering is mandatory — unbuffered MS-222 causes gill damage
  • Euthanasia confirmation requires 10 min post-cessation of opercular movement (AVMA Guidelines 2020)
  • Waste disposal — follow institutional chemical waste procedures; do not pour down drain
  • PPE — wear gloves when handling; MS-222 can cause skin sensitization with repeated exposure

Frequently Asked Questions

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