Most goldfish get sick at one time or another. One may have a floating issue
caused by constipation, and another may be sensitive to nitrates; bottom
sitting. If your fish has been kept improperly, it could be suffering from
oxygen deprivation or it could have a bacteria infection. Whatever ails your
fish, it's difficult to know if the fish is going to improve with the proper
care and time, or if it's just going to decline; getting worse with each passing
day. It's very difficult to know when and if it's the right time to euthanize a
You may hear someone say, just let nature take its course, but in the wild, a sick fish will quickly fall prey to a large and healthy one; it won't suffer for long. In captivity, our fish can linger for weeks, even months before passing. We all have to use our own good judgment here; trust our instincts.
Euthanizing a goldfish can be relatively easy and painless; for the fish that is. Goldfish become dormant in colder temperatures; being a cold water fish it has no core body temperature. Its temperature is always the same as its environment. This can be a distinct advantage for the goldfish keeper. In a natural environment, goldfish live in outdoor ponds. In winter, the water temperatures may fall below freezing temperatures. Although they cannot survive being frozen solid for long periods of time, they can survive close to freezing temperatures for an unlimited time. Reason being, their organs shut down and they no longer require food or oxygen; much like a bear in hibernation. You may think this would be painful for the goldfish, but keep in mind, only warm blooded creatures, such as dogs, cats, and humans alike find cold temperatures painful.
The Big Chill method
1. Place the fish in a large freezer bag filled with its tank water and seal:
Bag should be proportionately sized so that the fish can swim around a bit
2. Place the plastic bag inside of a brown paper sack or cardboard box:
Sack or box is for discretion
3. Place the sack or box in the refrigerator for a minimum of 24 hours, so that the fish will become completely dormant.
4. Place the sack or box in the freezer for a minimum 36 hours.
5. Dispose of sack or box at your discretion
Another method is using clove oil; which unlike the big chill, may cause a
certain level of discomfort for fish.
1. Prepare bath using 5 to 10 drops of clove oil per one gallon of tank water; mix well before placing fish in water; allow fish to remain in bath for 5 minutes; then add 20 drops of clove oil per one gallon of tank water; mix well before pouring into fish's container. Allow fish to remain in bath for 20 minutes before disposing.
On rare occasions, goldfish have been known to come back from the dead. Read the story of how one goldfish leaped from its tank and was found dried out; rock hard hours later, only to come back to life when returned to its tank. Fish Out of Water There are many such goldfish stories. Every creature big or small has a very strong survival instinct. Euthanizing is often a very tough decision to make. Consider this option only when there's no chance for life, and their suffering is too much for the both of you.