Fish and Aquatic Conservation

Oxytetracylcine dihydrate (Terramycin® 200 for Fish) INAD #9332

photo of a Rainbow trout swimming
Rainbow trout. Credit: Ryan Hagerty/USFWS


Terramycin 200® for fish is an aquaculture premix containing oxytetracycline dehydrate (OTC) and is available through Syndel USA. OTC medicated feed can be purchased from aquaculture feed mills. OTC medicated feed can be used to treat bacterial diseases or to apply a skeletal mark on the fish. The primary goal of field studies conducted under INAD #9332 is to generate additional OTC-medicated feed efficacy data which can be used to expand the existing OTC label claims. Five treatment options are allowed, and disposition of investigational animals (including withdrawal times) vary with treatment regimen. The treatment regimen most frequently used by Investigators is to administer OTC in feed at 2.5 – 3.75 g active drug/100 lbs fish/day for 10 consecutive days. All labeled use must follow the approved label and go through the Veterinary Feed Directive. This INAD is limited to specific marine and freshwater fish species (the food-use authorization located in the study protocol contains a list of all species that can be treated). To participate in the INAD Program for OTC medicated feed visit the data collecting site.

Please read the Study Protocol prior to any treatments. It contains the protocol, MSDS, and a copy of the forms to be used as a guide for collecting data that will be entered into the online INAD database. The FDA authorization letter(s) for this INAD is currently only available by emailing Bonnie Johnson.

INAD objective/purpose: Collect supportive and pivotal data needed to establish the effectiveness of oxytetracycline (OTC) when fed as a feed additive to 1) control mortality caused by bacterial diseases in a variety of freshwater and marine fish, and abalone; and 2) mark skeletal tissue of finfish.

Drug Name
Oxytetracycline dihydrate (Terramycin 200® for Fish; TM200)

Drug Source
Syndel USA
1441 W Smith Rd
Ferndale, WA 98248 USA

Jason Montgomery
Phone: 800-283-5292; Fax: 360-384-0270
Website: http://

Target pathogen(s): Bacterial pathogens susceptible to oxytetracycline, exclusive of already approved claims.

Method of administration: Medicated feed treatment

Treatment dosage:

  • Standard therapeutic finfish dose: 2.5 - 3.75 g OTC per 100 pounds fish per day.
  • High therapeutic finfish dose: 10 g OTC per 100 pounds fish body weight per day.
  • Standard abalone dose: up to 6.0 g OTC per 100 pound abalone body weight per day.
  • Skeletal marking dose: same as standard or high therapeutic finfish dose.

Treatment regimen:

  • Option A: standard therapeutic finfish dose; 10-day treatment duration (all salmonids).
  • Option B: high therapeutic finfish dose; 14-day treatment duration; temp > 4°C (all finfish).
  • Option C: standard therapeutic finfish dose; 10-day treatment duration (non-salmonid freshwater and marine fish).
  • Option D: standard abalone dose; 14-day treatment duration.
  • Option E: skeletal marking at standard therapeutic dose, 10-day treatment duration; skeletal marking at high therapeutic dose, 14-day treatment duration.

Investigational Withdrawal period:

  • Option A: 21 days.
  • Option B: 70 days.
  • Option C: 40 days.
  • Option D: 35 days.
  • Option E (standard dose): 21 days (salmonids); 40 days (non-salmonids).
  • Option E (high dose): 70 days (all finfish).
  • No Investigational withdrawal period is required for treated fish that will not be susceptible to legal harvest or slaughtered for market for the appropriate number of days as specified in the Options listed above.

Required test parameters:

  • Investigator must collect mortality data throughout the 5 day pre-treatment, treatment, and 10 day post-treatment periods. Investigator should also report general fish behavior and any possible adverse effects relating to treatment.

Limitations or restrictions on use of drug:

  • Not for use for existing FDA-approved claims for TM200.
  • Investigator must follow all instructions in the Study Protocol for INAD 9332 regarding drug acquisition and handling, fish treatment and disposition, and data reporting requirements.
  • Drug discharge must be in compliance with local NPDES permitting requirements.

Required INAD fee: $700/facility/year

AADAP Contact Information:
Ms. Bonnie Johnson, FWS-AADAP
Phone: 406-994-9905
Fax: 406-582-0242