Can Fish Jump?
Can fish jump? Oh yes, fish jump. Many fish are excellent jumpers in fact, and can clear over a foot in a vertical jump. I am not just talking about wild fish here either, even small aquarium fish are quite capable of jumping out of their tanks, and many do so on a regular basis.
Why Do Fish Jump?
Jumping is an ability that allows fish to travel up stream to spawn, to escape predators and to escape water conditions they don't like. When fish jump in aquariums it is often to escape dirty water, because they are being chased by other fish in the tank, or because they see another fish nearby that they want to attack. The latter often occurs with betta fish who are highly aggressive, and if placed next to another betta fish will often try to leap out of their own tank and into the other fish's tank. This never has good results. If they succeed in leaping out of their tank and into the other fish's tank, you will end up with two severely maimed or dead fish. If they fail, then you will have one dead fish.
How Can I Stop My Fish From Jumping?
Bettas are not the only fish that can jump however, pretty much all fish are capable of surprisingly large jumps. I myself recently lost a cichlid that I never thought would be able to jump out of its tank. For this reason, tank covers are essential. If you don't have one, you can use saran wrap (making sure you leave some space for air to circulate over the top of the water,) as a temporary cover. If you have larger, expensive fish, I recommend ensuring that you have a cover on your tank before you bring them home. There is nothing worse than a prize fish dying because it threw itself out of its tank.
Aside from a tank cover, always make sure that your fish are swimming in clean water. Even if water looks clean, it can sometimes be quite poisonous due to build up of ammonia and nitrites. Read this article on how to test for Ammonia and Nitrites.
Make sure that aggressive fish are not harassing one another too much. Deaths by jumping often occur after a new arrival has been introduced to the tank, so if you add new fish, make sure that they are not being bullied to the point where they will try to leap out of the tank. Some fish have even leaped out of the filter inlet.
Being aware that all fish, no matter what kind they are, can jump is the first step to making sure that your aquarium is safe.