Invasive Pond Species

Be careful when you add anything living to your pond. State and federal laws are in place about the status of invasive species banned from being released into the wild. This is because of the damage invasive species cause to the natural ecosystem.

What are invasive species?

An invasive species is simply a species that is not native to a specific place. As such, there’s concern that it could reproduce and spread. As a result, they can cause damage to the environment, the economy, and even humans.

A few years ago newts were banned from being transported over state lines. Fisherman used them as bait in freshwater lakes while setting free any unused ones. This creates more competition for food sources, affecting other animals in the ecosystem.

Invasive Species - Natural Pond Lover
A fine how do you do - An invasive Cuban tree frog

Introduced species can also spread diseases to other inhabitants of the ecosystem. Native species don’t have the necessary antibodies to fight off foreign diseases. Especially in aquatic environments such as ponds, lakes, and rivers. Finally, invasive species can wipe out plant life that is vital to an ecosystem.

Snails

Native snails are great for the ecosystem of a natural pond. They are an important factor in achieving clear pond water. Invasive snails such as the island apple snail, are harmful to a pond that doesn’t have natural predators to keep populations in check. They rip through oxygenating plants leaving little behind. They also get very large. You may notice that most native snail species in the states are small. Temperate and subtropical states have colder/cooler winters than tropical countries in Central and South America. Since they have a much shorter warm season, snails from temperate climates stay smaller. 

There are one native species of apple snail in Florida. The problem is that it’s hard to tell them apart from the non-native apple snails when they are young. I keep a colony of Florida apple snails in my bass pond. There’s a reason it’s a ‘small’ colony. These snails gather at the embankment where the water is only an inch or two in depth. At night, raccoons come along and pick them off. I always find empty apple snail shells around the grassy areas of my pond. While I still consider the raccoon a pest, it is helpful that they keep the Florida apple snails in check. As long as your pond liner is properly buried and secured, raccoons won’t cause too much of a problem.

Fish

Did you know that fish of the carp family, including koi and goldfish, are not native to the United States? Whether or not these fish are invasive isn’t up for debate. They’re available everywhere and remain very popular. All pet shops carry them, in fact, they’re a long-standing staple of the industry. In Florida, you can buy koi and goldfish legally and add them to your pond. Even so, never release any member of the carp family into the wild. They have done real damage in the Great Lakes area. Goldfish get large and easily survive cold winters.

Tilapia is another fish you should avoid not just because they’re invasive. They’re a dirty fish and get too large for ponds. They eat a lot of beneficial vegetation. My first pond contractor said that tilapia were strict vegetarians. In actuality, they’re omnivores. I’ve seen them take live prey with my own two eyes.

Frogs

Avoid African clawed frogs like the plague! These frogs are readily available at most pet stores. They are aggressive predators and prolific breeders. If you live close to a body of water outside your property, there is a chance they may infest other wetlands during extended periods of rain.

An incident occurred in San Francisco when someone released African clawed frogs in a small public pond. They overtook the pond resulting in it being drained on at least two occasions.

Brown anole | Natural Pond Lover
The brown anole is an invasive lizard commonly found in Florida. They compete with they native green anole.

I’m not sure if the second eradication attempt was successful so the African clawed frogs might still remain. This is why you should never add these frogs to your pond. They are also sometimes sold as African dwarf frogs.

Check your local laws and state regulations

Always check your local and state laws to make sure that you are not putting your pond or the environment around you at risk. Besides screwing up the ecosystem, new and stricter laws apply when it comes to buying plants and animals. Yes, certain plants are invasive too!

While adding a pond to your property is very good for the environment, it can also become harmful if it introduces invasive species which are destructive. It’s up to all of us as responsible pond owners to make sure that we’re not adding more stress to our rapidly deteriorating world.

Avoid releasing invasive species in nearby waterways. As a general rule, avoid these species altogether. It’s better to go with animals found naturally in your range. Domestic fish and animals have a better chance of surviving the winter which is reason enough to avoid invasive animals.

Two invasive species in Florida

The picture above to the right is a Cuban Tree Frog. Purposely introduced to Florida, they have caused damage to the states delicate ecosystem. They grow large and have pretty much wiped out our native green tree frog. Cuban tree frogs have voracious appetites and eat our native reptiles and amphibians. They eat a lot of bugs too. While that may sound like a good thing, they are competing with our native frogs (and toads).

The brown anole follows a similar path as the Cuban tree frog. The brown anole originated from Cuba and the Bahamas. They have taken over Florida and now our native green anole lives only in the treetops. It seems like invasive species that can establish themselves always win.

Who is to blame?

It is important to note that no invasive plant or animal has done more damage to a natural ecosystem than human beings. After all, we introduced these invasive species, to begin with. Whether accidental or on purpose, we are still to blame.

Take the red imported fire ant, an absolutely devastating pest. They came in on trade ships from Central and South America.

Cuban Tree Frog | Natural Pond Lover
The invasive Cuban tree frog lays its eggs in freshwater ponds.

Then you have the Burmese pythons of the Everglades which originated from the pet trade.

We can’t go back and change what has already been done but be aware that introducing invasive plants and animals to our ponds can cause harm to the environment. As pond and nature lovers, that’s the last thing we want, right?

Invasive Pond Species