Fish vets have described a new method of administering medication to fish via a catheter inserted into the body cavity.
Many drugs, especially antibiotics, perform best when they are injected into the body cavity of the fish. But doing this involves removing the fish from the pond, anaesthetising it, and re-injecting the patient each time a dose is due.
The new technique, which has been developed by a team of veterinarians from the Department of Clinical Sciences at North Carolina State University's College of Veterinary Medicine, uses a 23-gauge butterfly catheter to produce an injection port for the next dose, which means the fish don't need to be jabbed again when the next dose is due.
The scientists set up a trial using 20 Koi to test the performance of their intracoelomic catheterisation technique against the traditional form of injecting the medication into the body cavity of the fish with a needle.
The non-catheterised Koi were injected each day with a drug using a needle inserted at the same place as the catheter in the catheterised fish, then at the end of the trial, the fish were examined to see what effect the drug delivery had.
All of the catheterised fish survived unharmed and the new method of drug delivery was just as effective as injecting them each day with a hypodermic needle.
The team believe that their technique, which allows fish to be precisely dosed with drugs without removing them from the water, could be highly beneficial when daily or more frequent dosing is required.
For more details see the paper: Lewbart GA, Butkus DA, Papich MG, Coleman AK, Krum HN, Noga EJ. (2005) - Evaluation of a method of intracoelomic catheterization in koi. J Am Vet Med Assoc. 2005 Mar 1;226(5):784-8.