Preface: There has been much controversy over Chemoprophylaxis vs. Observational Quarantine in our hobby. The purpose of this article is to discuss the best practices for implementing both techniques, and to weigh the pros & cons of these two different methods of quarantining saltwater fish.
Chemoprophylaxis - the use of drugs to prevent disease.
The primary argument for advocating this approach is how "disease polluted" the supply chain is, meaning that the odds of buying a diseased fish are high. (Although this seems to be more of a problem in the US than some other parts of the world.) Many hobbyists cannot properly identify fish diseases and/or some diseases have no obvious visible physical symptoms. Therefore, chemoprophylaxis is a practical way to "cast your net wide" to treat for the most common/virulent diseases. Which include: Ich, Velvet, Brooklynella, Uronema, Trichodina, and Flukes. Bacterial infections and internal pathogens are more commonly treated on an as-needed basis.
So what are the best methods for prophylactic QT? First, it's best to dose medications in a rockless tank (substrate is optional). Porous rock is notorious for absorbing certain medications, and the additional nitrifying bacteria it contains will just further increase biodegradation of the meds. Basically, you want to apply medications in an environment that is as sterile as possible. There are other tips mentioned here, including increasing gas exchange (oxygen) while using medications. Below are different QT protocols which utilize chemoprophylaxis; all proactively treat for the most common/virulent diseases listed above:
** DO NOT dose General Cure within 48 hours of Metronidazole, since General Cure contains Metronidazole. When using Prazipro, it is fine to combine with Metronidazole. :Thumbs_up_green:
*** You can deworm with copper/metro or chloroquine already in the water, although it is better/safer to do so either before or after those treatments are used. For example, if transferring after 14 days then it would be better to apply General Cure or Prazipro in this 2nd tank.
**** You can safely use both General Cure or Prazipro with copper/metro (although observe the 48 hour rule with GC + metro). You can safely combine General Cure with chloroquine. However, DO NOT use Prazipro with chloroquine. Mixing those two will sometimes result in a catastrophic bacterial bloom (very cloudy water) which will use up the oxygen in the water and suffocate the fish.
The argument against chemoprophylaxis centers around possible damage done to the fish (especially their gut microbiota) and/or inability to survive the treatment(s). It is difficult to quantify the latter - how many fish that die in QT would have died anyway had they been placed directly in the DT? Studies linking long-term damage to fish from medications are very limited. I think the only conclusive one I have ever seen involved liver & kidney damage after several months of copper exposure.
The other few studies exposed fish to extremely high concentrations of certain medications (which would harm/kill almost anyone).
I personally have kept fish for 10-15 years following exposure to medications (including copper) in QT. However, it is impossible to say what medications you apply may or may not be harmful. There is some anecdotal evidence that Formalin (which contains formaldehyde - a "probable human carcinogen") may lead to reduced life expectancy for certain fish.
Continue to Part 2: Chemoprophylaxis vs. Observational Quarantine Part 2
Chemoprophylaxis - the use of drugs to prevent disease.
The primary argument for advocating this approach is how "disease polluted" the supply chain is, meaning that the odds of buying a diseased fish are high. (Although this seems to be more of a problem in the US than some other parts of the world.) Many hobbyists cannot properly identify fish diseases and/or some diseases have no obvious visible physical symptoms. Therefore, chemoprophylaxis is a practical way to "cast your net wide" to treat for the most common/virulent diseases. Which include: Ich, Velvet, Brooklynella, Uronema, Trichodina, and Flukes. Bacterial infections and internal pathogens are more commonly treated on an as-needed basis.
So what are the best methods for prophylactic QT? First, it's best to dose medications in a rockless tank (substrate is optional). Porous rock is notorious for absorbing certain medications, and the additional nitrifying bacteria it contains will just further increase biodegradation of the meds. Basically, you want to apply medications in an environment that is as sterile as possible. There are other tips mentioned here, including increasing gas exchange (oxygen) while using medications. Below are different QT protocols which utilize chemoprophylaxis; all proactively treat for the most common/virulent diseases listed above:
- Copper (14 or 30 days*) + Metronidazole (dosed every 48 hours at least 3x). Dose API General Cure** or Prazipro 2x in order to deworm. (Use this treatment calendar to determine when is the best time to add the second dose.)
- Chloroquine (14 or 30 days*). Dose API General Cure** or Prazipro 2x in order to deworm. (Use this treatment calendar to determine when is the best time to add the second dose.)
- Hybrid Tank Transfer Method
** DO NOT dose General Cure within 48 hours of Metronidazole, since General Cure contains Metronidazole. When using Prazipro, it is fine to combine with Metronidazole. :Thumbs_up_green:
*** You can deworm with copper/metro or chloroquine already in the water, although it is better/safer to do so either before or after those treatments are used. For example, if transferring after 14 days then it would be better to apply General Cure or Prazipro in this 2nd tank.
**** You can safely use both General Cure or Prazipro with copper/metro (although observe the 48 hour rule with GC + metro). You can safely combine General Cure with chloroquine. However, DO NOT use Prazipro with chloroquine. Mixing those two will sometimes result in a catastrophic bacterial bloom (very cloudy water) which will use up the oxygen in the water and suffocate the fish.
The argument against chemoprophylaxis centers around possible damage done to the fish (especially their gut microbiota) and/or inability to survive the treatment(s). It is difficult to quantify the latter - how many fish that die in QT would have died anyway had they been placed directly in the DT? Studies linking long-term damage to fish from medications are very limited. I think the only conclusive one I have ever seen involved liver & kidney damage after several months of copper exposure.
The other few studies exposed fish to extremely high concentrations of certain medications (which would harm/kill almost anyone).I personally have kept fish for 10-15 years following exposure to medications (including copper) in QT. However, it is impossible to say what medications you apply may or may not be harmful. There is some anecdotal evidence that Formalin (which contains formaldehyde - a "probable human carcinogen") may lead to reduced life expectancy for certain fish.
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