What she recommends is to do injections IM there can be drawbacks on doing IM but to date have not had any problems with welts. Below is a description of the 3 ways to inject.
There are three injection sites on a Koi; Intraperoteneal (IP), Intramuscular (IM), and Intravenous (IV). IM is the most common & 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.
IP 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 drawback 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.
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.
What we recommend is to inject on one side and then move to the opposite side for next injection. Start toward backside and on each rotation move up a bit for the next injection. We have found by the 3rd or 4th injection along with topical treatment you can start to see improving results.
We found that by using a 30" Smart Koi Net that we had less stress and a much easier time holding and injecting Koi. You can leave Koi submersed in water without having to remove them to inject. You can also do the topical treatment at the same time and then release back to pond or QT.
We find it best to clean the open ulcer the first 2-3 days of injections, after that we just use the ointment and denture powder only without scrubbing wound. The reason we don't after the first few days is we do not want to destroy any tissue that is regenerating over ulcer. We use hydro peroxide with a cotton swab to clean and remove any dead tissue and clean under the layer of scales around wound. After doing that we apply Debride is a medicated ointment or Panalog from your vet.
Panolog (Only available through Vet) is a formulation that contains medications with anti-puritic, anti-bacterial, anti-fungal, anti-allergic and anti-inflammatory properties.The ointment provides relief against the symptoms of variety of ear and skin infections that are perilous for dogs and cats. We also use Tricide Neo® as topical powder for anti-bacterial to the open ulcer We then use denture powder to apply over ointment or Tricide-Neo to seal it it.
Precaution to only treat red, bloody wounds. Look closely at the ulcer before you catch the fish. If the ulcer is pink with a white rim do not scrub it with peroxide or iodine – it is already healing on its own.
At this time we also follow up with a medicated food for the next 2-3 weeks, feeding daily to all the Koi pond or QT. We found that Debride RX Medicated Koi Food is a triple antibiotic medicated food that fish will actually eat. Along with injection for the open ulcers and topical treatment and medicated food it will give you the 1-2-3 punch to heal your Koi.
Until then "Happy Ponding" from "Koiman"