Injecting Koi Fish

There are three injection sites on a Koi, Intraperoteneal (IP), Intramuscular (IM), and Intravenous (IV). IP is the most common  and the most effective method. Antibiotics or vaccines injected into the peritoneal cavity are absorbed into the fish’s system slowly as opposed to oral medication which will mostly pass straight through.




IM is the second choice for injection and is used if the Koi has ulcers that have broken through to the body cavity. Any medication injected into the peritoneal cavity in a fish of this condition could drain out through the ulcer. The draw back to IM is that the muscle tissue of the fish will contract and force some of the injected material to be squeezed back out the injection site. IM can sometimes leave visible welts from trauma to the muscle tissue.

1.Intraperoteneal (IP) Koi Injections

The actual IP injection is performed by injecting in the abdomen at a 45 degree angle between the caudal fins and the anal vent. The needle points towards the head of the fish and enters approximately 2/3 of the way from the anal vent, 1/3 back from the caudal fins (see Drawing 1). Insert the needle quickly, plung smooth but quick, & withdraw the needle. You may fill some resistance from cartlidge below the skins surface. If the fish is large and the cartlidge difficult to penetrate, you can insert the needle slightly to one side of the center line.

You can not avoid hitting a scale, so don’t waist time searching around with the needle. Scales will grow back if lost and since you are injecting on the underside of the fish, any temporary damage will not be visible.

The beauty of the IP injection performed under sedation is that the fish does not thrash about. Without the thrashing, you will not lacerate an organ. In addition, with the fish relaxed & upside down, the organs tend to settle out of the way a bit. You might still puncture an organ, but with the fine needle pushed in and pulled out cleanly, there will be little danger. I have never lost a fish from injecting this method.

2. Intramuscular (IM) Koi  Injections

Intramuscular (IM) Injections

The IM injection is performed with similar needle angle and direction, but it is in the muscular tissue along and to the side of the dorsal fin (see Drawing 2). With a muscular injection, you must keep the needle in the muscle tissue and press the plunger as you with draw the needle giving room for the fluid to enter. Because of this, the needle must be inserted deeply.


2.1 Dorsal muscle

Dorsal Muscle Injections

This injection site offers the opportunity for deep Intra Muscular injections. Slip the needle underneath a scale, aiming towards the nose of the fish and administer the injection. Keep some pressure on the injection site with a thumb for a few seconds to ensure better distribution of the antibiotics and to prevent it from being forced out by contracting muscles. Topical treatment can be applied to the injection site to prevent bacterial infection. Some scales may be lost because of the possibility of a non-contagious cyst that can develop, or a scale that has been pierced will be dislodged when the needle is extracted. This site is risky from an aesthetical point of view and is not recommended for valuable koi.


2.2. Caudal muscle

Caudal Muscle Injections

This injection site offers the opportunity for injection into the red muscle of the fish that will ensure rapid distribution of the antibiotics through the fish. The needle is also slipped underneath a scale. The procedure is similar to the injection into the dorsal muscle, and is also not recommended for valuable fish.



2.3. Base of the dorsal fin

The injection site is located at the rear of the dorsal fin, just behind the last fin ray. There are no scales at this site and offers an injection site without the immediate risk of scale losses. If a non-contagious cyst develops, scales may be lost. Insert the needle just behind and slightly to the side if the last fin ray, aiming towards the front of the fish at a 45-degree angle. Because this is also an IM injection, apply a little pressure to the injection site when the needle is withdrawn.


2.4. Pectoral muscle

An injection into the pectoral muscle is the best injection site for an IM injection, mainly because any cysts will be hidden from view and there are no scales. As with all injection sites, this one is also not without risk. Some medications are harsh on muscle tissue and the muscle of a fish may harden, rendering the fin immobile, especially in smaller fish. It however remains the IM injection of choice if the visual damage must remain as little as possible. The accompanying photo demonstrates how the pectoral fin is lifted away from the body exposing the muscle. The injection is administered and the injection site lightly massaged to ensure even distribution of the antibiotic. Topical treatment can also be applied to the injection site to prevent bacterial infection.

The injection site is located at the rear of the dorsal fin, just behind the last fin ray. There are no scales at this site and offers an injection site without the immediate risk of scale losses. If a non-contagious cyst develops, scales may be lost. Insert the needle just behind and slightly to the side if the last fin ray, aiming towards the front of the fish at a 45-degree angle. Because this is also an IM injection, apply a little pressure to the injection site when the needle is withdrawn.




3. Intravenous Koi Injections

Intravenous Injections (IV), Some antibiotics are developed for injection directly into the bloodstream, because it loses it's effectiveness quickly. This can be achieved through an intravenous injection to the base of the caudal fin. The main problem that one experience with this specific injection is the ability to penetrate the vein that runs through the centre of the fish. The best way to determine when the needle is placed correctly is to turn the fish upside down and then to insert the needle at the base of the caudal fin. If you draw the plunger back a little, blood should be entering the syringe. When this happens, the plunger can be depressed and the antibiotic will be deposited into the bloodstream. This should not be attempted unless it is absolutely necessary.

Intravenous Injections

Source:
- http://www.lonestarkoi.com/Articles/needles.html
- http://www.koi4u.co.za/index.php?option=com_content&view=article&id=58&Itemid=49