Mending a Split Fin

How to successfully mend a split fin on a Koi with super glue. Jim Phillips takes us through the proceedure.


Mending a Split Fin


A split pectoral fin is a common injury in Koi. It can happen during netting or transportation. That is why it is important to use a proper Koi net and sock net when catching your fish.

If the tear in the fin is small, I usually leave it alone. If the water quality is good, the split fin will heal itself without infection. For larger tears, medicines can be applied and the split fin can be joined with sutures. This procedure has to be performed under anaesthetic.

The two sides of the split fin must be carefully aligned. If you use suture material that dissolves, the tear should heal before the suture material disappears. With other suture material the sutures have to be removed, requiring another anaesthetic.

While I was in Holland for the 13th Nishikigoi Vereniging Nederland Show, I visited some Koi dealers. The people in Holland are very friendly and very keen to show you their Koi. At Kyoto Koi Farm, the owner, John Gieles was happy to show some of the other judges and myself around his facility.


Having tea at Kyoto Koi Farm, Merselo, Holland

In one of his ponds I noticed a very nice Asagi. Unfortunately, it had a split pectoral fin. The split was the full length of the fin. I was discussing the Koi with Ralf Boehner from Australia and Kao Chung-Feng from Taiwan. Ralf said that he would treat such a bad tear in the pectoral.



Asagi with a split fin

Providing the tear was not infected, Ralf said he would use super glue to hold the fin together and help it heal. Ralf explained that super glue was developed as part of a research programme of the American military to close wounds in battle situations.

I had heard of super glue being used on fish and was fascinated by the discussion. John Gieles was keen to try this technique on his Asagi and produced some super glue from his shop. Together with Kao I helped to catch the Koi. Ralf used clove oil to anaesthetize the Koi. When the Asagi was anaesthetized it rolled over.

The Koi was placed on a baby's changing mat covered with plastic. John keeps this mat for his Koi operations. The fin was clean and not infected, it was carefully dried and super glue was brushed on to both surfaces of the split.

The fin was held in position for a few seconds until the glue held the fin together. Care was taken not to glue the Koi to the towel!



The fin is held together with super glue

The Koi took two minutes to come around. An air line was put into the bowl.




The Koi seemed absolutely fine and swam away with an intact fin.



The Koi seemed absolutely fine and swam away with an intact fin.

Ralf assured us that as the fin healed, the glue would dissolve. I was impressed at how simple the procedure was. It was certainly easier and quicker than suturing a fin.



Ralf Boehner - thats the way we do it in Australia!

The next time I have to attend to a badly split fin I think I will try this super glue method. On our way home, Kao stopped off at a shop to buy the same brand of glue that had been used on the Koi. He obviously planned on mending a few fins back in Taiwan.


The surgical team of Kao, John and Ralf.