Fish Health - Anaesthetics

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Do not use any form anaesthetic for just a injection, and not clove oil for other than destroying a fish, as it's too unreliable. Also they do not work under 230C, you are wasting your time, it's better over 250C.

Do not anaesthetise for a injection. You need fish mobile for the antibiotic to travel round the fishes system, it will only be present for around 1-6 hours and it may take a fish one hour or more to recover from anaesthetic.

Enlist the help of a friend. Never try to inject on your own. Use aquatic fish cleaner to clean the site. Make sure you and your friend are firing on all six and you know what you are about.

Don't hold the fish still why you read the first two chapters of war and peace.

When fish is out of the water, everything should be ready. The koi is in a wet sock which is on a wet towel. (Don't kneel on the wet towel or you will rush). Once fish is quiet and you have decided in which area of the fish you wish to proceed, then get on with it. Seal the wound with iodine and friars balsam (1 part Iodine to 4 parts balsam). The sooner fish is back in the water, the happier it will be and less stress will be involved.

Do not use anaesthetics when taking a scrape. Anaesthetic in some cases will kill what you are looking for or render most infections (parasite) non-mobile. e.g. costia which would be disastrous if missed, as scrape would look clear.

Use a koi sock and large towel, and a low solid surface, not a table or the fish will end up on the floor. This method can also be used for injections.

When inspecting a fish use a large (new) poly-bag. Don't roll the fish about in a net, or better still a framed floating inspection net. Similarly, all a blue inspection bowl will do is shock the fish as you inspect it. Fish bouncing off the sides blue bowls are fine if your just looking at the fish, but you cannot underneath in the same way as you can in a poly-bag. How many fish have been bought from blue bowls with ventral and anal wounds I wonder?

Only use anaesthetic when you want to apply topical treatments or inspect a wound prior to treatment. Also remember, every fish will react to anaesthetics in a different way. Some go under very quickly, some do Shakespeare on you. BUT don't increase doses if this happens, just wait. Have a recovery bowl ready with air stone and same water which fish was removed from.

When fully recovered, put the fish back into a hospital pond or tank. If going straight back into pond, which most do, inspect on a regular basic over the next few hours - visual only.

Make sure air is out of the syringe before you inject, and bend over needle as soon as you have finished. Use a new needle every time - I know it sounds daft, but some people don't.


healed ulcerNew tissue of a ulcer after successful antibiotic treatment is white, no matter what colour the fish is. It gradually fills out so it looks more like a scar than a healed wound and in some cases will rescale.

The timescale is dependent on water temperature, class of antibiotic, strength of infection and the amount of secondary infection present upon detection of wound.

Injection Wound

This wound has been caused by: poor area to inject - not forward enough, an unsterilised needle and a needle that was too small.

If you are in any doubt with any of the above, please contact me direct.