Laboratory Animal Care Facility (CRC)

Anesthesia and Euthanasia of Fish

Unit 004-021
Anesthesia and Euthanasia of Fish Using MS222

I. PURPOSE

To describe the use of MS222 for both anesthesia and euthanasia of fish.

II. ROLES AND RESPONSIBILITIES

  1. It is the responsibility of the PI, Graduate Student or LACF staff to terminate fish at the request of the PI

III. MATERIALS NEEDED

  1. Gloves
  2. Safety glasses
  3. Facemasks
  4. Small beaker
  5. Container with lid (marked “for MS22”)
  6. Prepared fish water
  7. MS222 (Tricaine: Sigma Cat. # A-5040, or Finquel Inc Part No. C-FINQ-UE from Argent Chemical Laboratories, or comparable)

IV. APPLICABLE LOCATIONS

To all facilities of the BU_CRC LACF

V. GENERAL PROCEDURES

  1. Put on gloves, safety glasses and facemask.
  2. Make a stock of MS222 to freeze:
    1. In a fume hood dilute MS222 in DI water. Label as MS222 Stock
      1. 80 mg tricaine powder
      2. 19.6 ml DD water
      3. Adjust pH to ~7 using sodium bicarbonate as needed.
      4. Store this solution in the freezer in 5 ml aliquots.

VI. TO USE AS AN ANESTHETIC

  1. Put on gloves, safety glasses and facemask
  2. Combine the following in a 250 ml beaker:
    1. Thaw one vial of about 5 mls. of the MS222 stock solution
    2. Mix into ~100 ml clean tank water.
    3. Transfer fish to be anesthetized into this container.

VII. TO USE FOR EUTHANASIA

  1. Put on gloves, safety glasses and facemask
  2. Combine the following in a small beaker:
    1. Thaw one vial of about 5 ml MS222 stock solution
    2. About 10 ml clean tank water.
  3. Fill a container (transfer container) with small amount of prepared fish water.
  4. Using dedicated net (from the tank from which the fish are being taken)   capture fish to be euthanized.
  5. Transfer fish into the transfer container.
  6. Bring transfer container with fish in it into work room.
  7. Drain as much water from container as possible. This will decrease the amount   of MS222 needed by making the concentration higher.
  8. Pour the diluted MS222 solution into the container.
  9. Put lid on container.
  10. Fish should be dead within 15 minutes.
  11. Remove fish from the solution, bag the carcasses and place in refrigerator. At      the end of the day the bag is brought to the freezer in the main LACF.
  12. Empty container into sink drain, run water for 2 minutes.
  13. Disinfect container and beaker in bleach solution (1: 10). Rinse thoroughly.

VIII. RECORDKEEPING

  1. Be sure to record on the day’s record. If an entire tank has been put down, note   it on the census sheet as well, and keep tank card in file in office.

Note: these amounts are based on the fact that MS222 at 50-100 mg/liter provides deep anesthetic and 25-35mg/liter of MS222 provides a light anesthesia.