An Ounce of Prevention

by John Howell


At recent Koi club meeting I presented information on Furogen, the Aeromonas Vaccine for Koi & Goldfish by Aqua Health Ltd. I found that “we” as hobbyist are confused a great deal about the vaccine. This article should provide some simple answers. First of all, ‘vaccinate’ does not automatically refer to injection. A vaccine can be in the form of a “immersion”, “injection”, or “orally” in food. (The oral vaccine is not yet available for Koi & Goldfish.) The purpose of a vaccine is to stimulate the normal immune defense system in our bodies through the production of “B” & “T” cells which specifically target the disease in question. In the case of “ulcer” or “whole in the side” disease, the Furogen (injectable) and the Furogen b (immersible) vaccine has been proven to be 99% effective. More effective than the vaccines we use in humans! After all the trouble I had last year with this disease which cost me a great deal in lost fish, scarred fish, & expensive treatments, this vaccine is great news!


Let me address some of the questions asked at the meeting:


  1. How big does the fish have to be to receive the vaccine? As soon as the baby fish loses the egg sack & has his first meal. Tests have shown that the immune system will respond well to the vaccine in fish as small as 2.8 grams.
  2. What is the best time of year to vaccinate? Any time of year is fine. Water temperature affects the speed of the immune response. To be effective, the vaccine must be applied 400oC days prior to exposure to the disease. So, if the water temperature is 25oC (which it is at my house now), then it will be 16 days (400 divided by 25) before the immune system is at full response. So, in the Winter, it will just take longer. Personally, I feel the injectable should be done early spring or summer & the immersible should be done early spring & again in the fall.
  3. How often do I have to vaccinate? The injectable form needs an annual booster. The immersible form needs a booster every 6 months.
  4. Should I use the immersible or the injectable? This question is a matter of size & economics. I immersed all my fish less than 8″ which included all of my Goldfish and my 4 newest (youngest) Koi. In 6 months when the immersed group is ready for a booster, I expect the Koi will be big enough to inject, so then I’ll only immerse the Goldfish. On the economic side, the injection costs the same regardless of the fish size because the amount injected is the same for all fish. The immersion cost is dependent on the “weight” of the fish because the larger the fish dipped, the more it will consume of the available vaccine. So, economically its cheaper to “dip” small fish and “inject” large fish. It was recommended to me to inject 12″ and above, but I use 8″ as the cut off size.
  5. I’m afraid to stick a needle in my beautiful fish! So was I at first, but it is actually easier than you would think. Statistics say there is a 5% risk factor involved with injection. I have done it only about 100 times, but have never lost a fish. It helps to put the fish asleep first by adding 5 drops of Oil of Clove (available at Health food store) per gallon of pond water in a bucket. Carefully catch one fish & put him in the Clove water. In a few seconds, he will go to sleep & turn on his side. Keeping him in the water, examine his entire body for parasites, ulcers, or other trouble. If he is clean, you can inject him Intra-peritoneal (IP) on the stomach in front of the anal vent but behind the pelvic fins. Hold the fish stomach side up against the side of the bucket closest to you. Insert the needle at an angle aimed in line toward the mouth. (This is easier shown on a diagram than explained) Depress the plunger, remove needle, & place the fish in oxygenated water to revive (about 15 minutes). My needle of choice is 27 gauge by ½”.
  6. My fish are sick, can I still vaccinate? No, if the fish is being attacked by the bacteria, his immune system is already trying to activate. The best thing you can do is take action to stop the disease by isolating him, proper use of antibiotics, salt, and warm water. Cure the fish first then you can vaccinate as soon as 3 days after redness of ulcers disappears.
  7. If I buy the vaccine, can I use part of it & store the rest? Yes and No. Your first vaccination by immersion requires a booster in 2 to 4 weeks with a single immersion required every 6 months after that. An open bottle of immersible can safely be stored in the refrigerator the initial 2 to 4 week period, but no longer. For the injectable, you can buy just what you need in individual pre-filled syringes. If you want to save money by purchasing a whole vial (50 injections) the unused portion can be kept for next year only if proper sterile practices are maintained. These include, always swab the vial with alcohol prior to each use, do not re-use needles, do not leave unrefrigerated longer than necessary, and most importantly DO NOT aspirate the needle (do not draw air into needle before inserting into vial). So, Swab the Top, Insert the Sterile Needle, Draw out Amount, & then Remove Needle. The vacuum created in the vial by not replacing the fluid with air should not be strong enough to automatically draw air through the rubber diaphragm. If the vial is spoiled, it can be identified next year by discoloration of the fluid & “goop” growing in it. Unused & Unopened vaccines in either form can safely be refrigerated for at least a year.


Aeromonas salmonicida (AS) & Aeromonas hydrophilia (AH) are 2 different bacteria & therefore there are 2 different vaccines. AH is the “new” strain out of Japan and so the vaccine is relatively new. Although the AH vaccine has been laboratory & field tested by Aqua Health Ltd according to the same standards as all their vaccines, I’m required to tell you that the USDA must perform its own tests before final licensing is given. In the meantime, the USDA classifies this vaccine as “autogenous” which means it can only be administered in conjunction with the AS vaccine (already licensed) and only on fish that came from Koi of Ok. (the field test site). Both vaccines are “formalin inactivated” which means that they come only from dead bacteria & CAN NOT cause the disease.


If you are still not sure, consider these questions:


  1. Are your fish too expensive to easily replace?
  2. Have you had this disease in your pond before?
  3. Do you like to add new fish or plants?
  4. Do your fish ever undergo stress?
  5. Do you take your fish to shows?
  6. Is your water quality ever less than perfect?


If you answered YES to even one of these questions, then this vaccine is definitely an Ounce of Prevention.