ill guppies-culling?

Question
Hey there

I have had tropical fish for a few years now, and currently have two tanks. In my largest (75ltr) I am working on breeding guppies and mollies. I have done a lot of research over the years, but have not yet been able to find an answer to this question. What is the kindest way to cull ill guppies, that have no chance of recovering? The illness I am referring to is unknown to me by name, however occasionally after my guppies give birth, their spines become bent, they lose weight very quickly despite eating, and often loose function of their swim bladders. I have had people tell me is TB, worms and "guppy syndrome". Either way I have tried many different medications to try and fix these poor girls, but they all end up dying in a painful manner. The American Veterinary assosiation states that an acceptable manner of euthanasia, is to drop the sick fish into cold water with a temp of 2-4 degrees Celsius, without the fish coming into contact with ice cubes which cause burns. However many people on forums say this is not acceptable?

I hate seeing my fish suffer, and I value them all highly. All I wish to do is end their suffering, and discontinue their lines. I don't have the heart to "smoosh" them, I couldn't do that to a sick bird/puppy/kitten, and I certainly cannot do it to my fish. I do regular water changes each week, and my pH and Nitrates are all normal. What do you think about this method of Euthanasia?
Thanks very much.
Lisa

Answer
Lisa,
This is how I do it and it is a very acceptable way.

First, anesthetize the fish with clove oil so that it is sleeping and unable to feel pain; then introduce a clear grain alcohol like vodka to ensure the fish will not wake up. Clove oil, or eugenol, is available at most drug stores and is sold as a toothache remedy. It has been used for years as a fish anesthetic for surgeries and tagging procedures. Clove oil will put a fish to sleep and ensure it feels no pain. THE FISH CAN WAKE UP FROM THIS SLEEP IF REMOVED FROM THE CLOVE BATH The last step of adding the vodka will ensure the fish expires.

For fish up to 3 inches (7.6 cm) in length, some simple steps can be followed. Add some tank water to a measuring cup or mixing bowl. The amount of tank water added to the cup or bowl should be measured and a note of it made. The fish should then be placed in the container. If the fish is in a clear cup, a dark towel placed around the cup may calm the fish.

Next you should fill a small, clean jar or bottle with tank water, leaving some room at the top. A baby food jar or pill bottle can work well for this. Then add 1 drop of clove oil in the jar or bottle, cap it, and shake the jar vigorously. The clove oil should emulsify, turning the water milky white.

Pour 1/4 of this emulsified mixture into the fish's container. The fish will begin listing as it starts to fall asleep. The fish should be allowed to sit for about 10 minutes.

The fish should be resting on the bottom of the tank when it has fallen asleep. It will look dead, but if watched closely, its gills will be breathing once every few seconds. If after 10 minutes the fish is still rising off the bottom and swimming intermittently, you should retrieve the jar or bottle of emulsified clove oil, re-shake, and add the same dose to the fish's container. Wait again for the fish to fall asleep. I have never had to do this a second time. It has always worked on the first try. Sometimes, you will need to add the mixture again.

Once the fish is asleep on the bottom, 20 to 25% white grain alcohol should be added. For example, if the fish is in 8 oz (240 ml) of water, 2 oz (60 ml) of vodka should be added. The fish should be allowed stay there for at least 20 minutes. After 20 minutes, the fish should be checked carefully for any gill movement. If there is no gill movement over a 60 second period, the fish has expired.

The fish will feel no pain if done this way. It is just like having a dog or cat put to sleep. This is the most humane way to do it. I know this is not an easy thing to do but it is important to  know that the fish will just slip away.