While there are tales of goldfish surviving for hours after a jump from their tank, sometimes a fish owner comes home to find their pet having permanently exited the environment. There are a few reasons -- from water issues to not getting along with tank mates -- that may spur a fish to make the leap; fortunately all can be prevented with a little habitat adaptation.
The Water's Cleaner on the Other Side
The most common reason a fish may try to jump out of their home is if the water is in an extreme: too dirty, too warm, too cold, too alkaline, too acidic or too low in oxygen. Consistent -- but not overabundant -- water changed and tank cleanings will help with these issues, and watch your goldfish for any indication he may be uncomfortable. Through use of a water pump, aerator or air stone and in addition to consistent water changes, make sure the water is well-oxygenated and clean.
Goldfish are fresh and cold water fish; they require clean water in a range from 65 to 75 degrees for maximum comfort. Water that is too warm will not only stress a goldfish, but also will drive him to seek cooler climes elsewhere; even if those are outside of the tank. Additionally, when the pH of the water falls below 5, or climbs above 8.5, your fish is at risk for pain, illness and possibly death. This acidity or alkalinity of the water can cause serious burns on the fins and gills of Mr. Sparkles, and prompt him to do anything for relief, including jumping from the tank.
An Itch That Can't Be Scratched
Parasites that are often invisible to us can be quite frustrating for a goldfish as they race around the tank, attempting to remove lice or worms. These small parasites latch on to the fish and create discomfort; so much so that the fish may leap from the water in search of relief. Signs that your goldfish may be infected by parasites include:
- Moving, circular objects on the body of your fish
- Constantly stressed fish
- Incessantly moving fish
- Red sores that grow larger
If you think your fish has parasites, treat him with parasitic medication available at local aquarium shops. If your fish seems to be suffering, or is lethargic, contact a local aquatic specialist for diagnosis and treatment recommendation.
Another reason for erratic behavior, including jumping from a tank, is stress. A too-crowded tank, bullying from other fish or fights over mating can all drive a fish over the edge, of the tank that is.
Goldfish should not be kept in bowls, despite the stereotype. Bowls are too small and not aerated enough for even a single goldfish, and will lead to potential leaping hazard far faster than a large tank would. For goldfish, the [ASPCA recommends](https://www.aspca.org/pet-care/small-pet-care/fish-care) 20-gallon tanks.
To keep Mr. Sparkles from jumping into the great abyss, make sure that his tank has a lid, and the lid can be securely fastened. If this cover also has lights, make sure you turn the lights off at night so your fish can get some much-needed sleep. Another option to a full tank cover is one of soft mesh. This allows fresh air to reach the surface area of the tank -- where goldfish get most of their oxygen -- while still preventing your finned friend from causing himself harm.
Keep the water level of your tank low enough that if your fish does make a leap for it, that he does not immediately strike the cover of the tank, and possibly injure himself. If you do happen to catch your aquatic buddy on the floor, even if you think he may be dead, place him back in the water of his tank. Some luck and good timing -- and future preventative fixes -- could see Mr. Sparkles back and swimming just fine.