No fishkeeper wants to read this page. But if you’re here, you’re doing the right thing by learning how to end a fish’s suffering properly. Clove oil is the most humane method available at home: the fish is sedated first, falls asleep, and passes without distress.
When is it the right call?
It’s time to consider it when a fish is suffering and has stopped responding to treatment. For swim bladder disorder, signs include:
- Stuck upside down, on its side or pinned to the surface or floor for weeks with no improvement
- No longer able to reach food, or has stopped eating
- Sores or red patches developing where its body is exposed to air or rubbing on surfaces
- Treatment (fasting, temperature, water quality, medication) has been tried with no change
If you’re unsure, an aquatic vet can assess the fish and can also carry out euthanasia for you.
What you’ll need
- Clove oil (100% pure, from a chemist or online)
- A clean container big enough for the fish to sit upright comfortably. For an adult discus, a 3-5 litre tub works well
- Water taken from the fish’s own tank, so the temperature and chemistry match
- A small jar with a lid, for mixing
The two-stage method
Why mix first? Clove oil doesn’t dissolve in water on its own. Always shake it vigorously in a jar of warm tank water until it turns milky, then add that mix to the container. Never drip neat oil onto the fish.
Stage 1: Sedate
- Fill the container with tank water and gently move the fish in. Keep the lights low and the room quiet.
- Mix roughly 4 drops of clove oil per litre of container water in your jar, shake until milky, and pour it in slowly.
- Wait 10-15 minutes. The fish will become calm, lose balance and settle on the bottom. This is the fish falling asleep.
Stage 2: Overdose
- Once the fish is fully sedated and doesn’t react, mix a much stronger dose: roughly 25 drops per litre. Shake well and add it.
- Leave the fish undisturbed for at least 1-2 hours. Don’t cut this short, as a fish can appear dead while still deeply anaesthetised.
How to confirm it’s done
- No gill movement for at least 10 minutes
- No response when gently touched
- Eyes stay fixed when the body is gently tilted (in a living fish, the eyes roll to stay level)
If you have any doubt, leave the fish in the solution longer.
Methods to avoid
- Flushing: slow, cruel, and can spread disease into waterways
- Freezing: ice crystals form in the tissue while the fish is still conscious
- Removing from water: a slow, distressing suffocation
Afterwards
Wrap the fish and place it in your general waste, or bury it deep in the garden away from ponds and watercourses. Never release it or flush it. Clean the container thoroughly before reusing it, and keep an eye on the rest of the tank in case the original problem was infectious.
Making this decision is part of caring for your fish properly. It’s never easy, but a calm, painless end is the last kindness you can give.
– Discus Switch