a man holding a big fish on the left and a wild hairy pig on the right
COURTESY OF DR STEPHEN BEATTY/MURDOCH UNIVERSITY (LEFT); ISTOCKPHOTO/GETTY IMAGES (RIGHT)
Paired Texts,

Monster Goldfish/Pigs on the Loose

Two different invasive species wreak havoc on their new environments

By Tod Olson
From the May/June 2021 Issue

Learning Objective: Students will compare and contrast information from two nonfiction articles about invasive species.

Lexiles: 600L-700L, 700L-800L, 800L-900L
Guided Reading Level: P
DRA Level: 37
Featured Skill: Compare and Contrast,
Common Core Standards
  • R.1, R.2, R.3, R.4, R.6, R.9, W.2, SL.1, L.1, L.2, L.6
TEKS Standards
  • TEKS Grade 3:
    1a, 1c, 3a, 3b, 6a, 6d, 6e, 6g, 6h, 7b, 7c, 7f, 7g, 9d, 12b

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Think and Read: Compare and Contrast

As you read, look for similarities and differences between the two stories. 

Monster Goldfish

How a little pet can become a giant problem 

By Tod Olson

COURTESY OF DR STEPHEN BEATTY/MURDOCH UNIVERSITY 

SWIMMING GIANTS
 This 4-pound giant was once a tiny goldfish. It was fished out of a river in Australia. 

They’ve taken over a river in Australia. They’ve invaded a bay in Canada and a lake in Colorado. They grow to enormous sizes and eat everything in sight. 

It’s the attack of the giant monster . . . goldfish? It may sound like a scary movie, but it’s not. Scientists say that giant goldfish are becoming a big problem in rivers and lakes around the world. And who caused the problem? 

We did—humans. 

They’ve taken over a river in Australia. They’ve invaded a bay in Canada and a lake in Colorado. They grow to huge sizes and eat everything in sight. 

It’s the attack of the giant monster . . . goldfish? It may sound like a scary movie, but it’s not. Scientists say that giant goldfish are becoming a big problem in rivers and lakes around the world. And who caused the problem? Humans did. 

They’ve invaded a river in Australia, a bay in Canada, and a lake in Colorado. They grow to enormous sizes, turn blue water brown, and eat everything in sight.

It’s the attack of the giant, killer . . . goldfish? It may sound like a bad horror movie. But scientists say that huge goldfish are becoming a, well, huge problem in rivers and lakes in many parts of the world. And who caused the problem?

We did—humans.

Major Damage 

Major Damage 


Sometimes pet owners get tired of their little Nemos and Dorys. They carry their bowls to the nearest stream and— splat! —they send their fish into the wild. This has caused many kinds of fish to become invasive species.

Invasive species are animals or plants that move from one area into a new environment where they don’t belong. They can do major damage.

Take goldfish, for instance. Freed from their small bowls and tanks, they can get more oxygen and food in the wild. They can grow and grow. They can eat up plants and fish eggs at the bottom of a river. They can force out fish that have called the river home for centuries. 

Sometimes pet owners get tired of their little Nemos and Dorys. They carry their bowls to a stream and splat! They send their fish into the wild. This has caused many kinds of fish to become invasive species.

Invasive species are animals or plants that move from one area into a new environment. They don’t belong in this new environment. And they can do major damage.

Take goldfish, for instance. Outside of their small bowls and tanks, they can get more oxygen and food in the wild. They can grow and grow. They can eat up plants and fish eggs at the bottom of a river. They can force out fish that have called the river home for hundreds of years. 

Some pet owners get tired of their little Nemos and Dorys. They carry their bowls to the nearest stream, and splat! They send their fish into the wild.

It seems kinder than flushing a rejected pet down the toilet. But this “aquarium dumping” has caused dozens of kinds of fish to become invasive species in rivers and lakes around the world. Invasive species are animals or plants from one area that invade a new environment where they don’t belong. These invaders, such as the goldfish, can do major damage.

Freed from their tiny bowls and tanks, goldfish have a bigger oxygen supply and more food. They grow and grow. They gobble up plants, fish eggs, and other treats at the bottom of a river. They can crowd out fish that have called the river home for centuries.

Solving the Problem 

Solving the Problem 


Once goldfish move into a river or a lake, they are hard to get rid of. One group in California found a solution for unwanted goldfish. The group built a special pond just for these abandoned fish. The goldfish can live in the clear, cool waters of the pond without harming native species.

Sometimes it’s nature that cleans up the messes that humans create. In 2015, thousands of goldfish took over a lake in Colorado. But then a flock of hungry pelicans arrived. They ate up all the invaders in the lake.

Still, the best way to protect native wildlife is to keep pet fish out of rivers, lakes, and streams in the first place 

Once goldfish move into a river or a lake, they are hard to get rid of. One group in California found a solution for unwanted goldfish. The group built a special pond just for these fish. The goldfish can live in the clear, cool waters of the pond without harming native species.

Sometimes nature cleans up the messes that humans create. In 2015, thousands of goldfish took over a lake in Colorado. But then a group of hungry pelicans arrived. They ate up all the goldfish in the lake.

Still, the best way to protect wildlife is to keep pet fish out of rivers, lakes, and streams in the first place. 

Once goldfish move into a river or a lake, they are hard to get rid of. Poisons that can kill goldfish can harm native species as well. The best way to protect native species is to keep aquarium fish out of rivers, lakes, and streams in the first place.

One environmental group in San Francisco has made it easier for pet owners to say goodbye. The group built a pond just for unwanted goldfish. In the cool, clear waters of the pond, abandoned fish can lead a long and happy life without endangering native wildlife.

But now and then nature solves its own problems. In 2015, officials in Colorado discovered that several thousand goldfish had taken over a lake near the city of Boulder. They thought about draining the entire lake and refilling it. But then a flock of hungry pelicans arrived and ate up all of the invaders.

Sometimes nature can clean up the messes that humans create.

Pigs on the Loose    

Wild pigs in Texas and beyond are eating everything in sight. Can they be stopped? 

ISTOCKPHOTO/GETTY IMAGES 

BIG PIG

Wild boars have tusks that can be up to 18 inches long. Their snouts can be up to 14 inches long! 

More than 500 years ago, explorers from Europe sailed to the Americas. They brought along special passengers: eight squealing, snorting pigs.

The explorers hoped that the pigs would grow in number and become food for the settlers. The plan worked—sort of.

Today, the descendants of those first eight pigs are fat and happy. They’re also causing big problems. Six million wild pigs now run free in at least 35 states. They chew up soccer fields and golf courses. They gobble up baby birds and turtle eggs. They devour just about any crop a farmer can plant.

And so far, no one has been able to stop them. 

More than 500 years ago, explorers from Europe came to the Americas. They brought along special guests: eight squealing, snorting pigs.

The explorers hoped that the pigs would grow in number. Then they would become food for the settlers. The plan worked—sort of.

Today, the descendants of those first eight pigs are fat and happy. They’re also causing big problems. Six million wild pigs now run free in at least 35 states. They chew up soccer fields and golf courses. They gobble up baby birds and turtle eggs. They devour just about any crop a farmer can plant.

And so far, no one has been able to stop them. 

More than 500 years ago, explorers from Europe came to the Americas. They brought along some special passengers: eight pigs that squealed and snorted their way across the ocean.

The idea was that the pigs would thrive in their new land and become food for the settlers.

The plan worked—sort of.

Today the descendants of those first eight pigs are fat, happy, and causing huge problems from Florida to California. Six million wild pigs now run—and eat—free in more than 40 states from coast to coast. They chew up soccer fields and golf courses. They gobble up baby birds and turtle eggs. They scrounge, graze on, or root out just about any crop a farmer can plant.

No one knows how to make them stop.

Gobbling Monsters 

Gobbling Monsters 


Wild pigs are also known as boars. They’re different from pigs found on farms. They grow thick, stiff hair to protect them from the cold. Fearsome tusks stick out from their lower jaws. Their snouts help them dig up everything from potatoes to peanuts. They can smell food up to 7 miles away and 25 feet underground.

Texas is home to half of the country’s wild pig population. The state is trying to find new ways to stop the animals. The Texas government allows hunters to kill the gobbling monsters at any time of year. And the state’s farmers use high- tech tools to catch the boars. 0

Wild pigs are also known as boars. They’re different from pigs found on farms. They grow thick, stiff hair. This hair protects them from the cold. Scary- looking tusks stick out from their lower jaws. Their snouts help them dig up everything from potatoes to peanuts. They can smell food up to 7 miles away and 25 feet underground.

Half of the country’s wild pigs live in Texas. The state is trying to find new ways to stop the animals. The Texas government allows hunters to kill the gobbling monsters at any time of year. And the state’s farmers use high-tech tools to catch the boars. 

These four-legged outlaws, also known as boars, are a little different from pigs found on farms. They grow thick, bristly hair to protect them from the cold. Fearsome tusks, up to seven inches long, jut from their lower jaws. Hard, gristly cartilage in their snouts helps them dig up everything from potatoes to peanuts. They can smell food up to 7 miles away and 25 feet underground.

Texas is home to half the country’s boar population, and the state is trying to find new ways to stop the wild pigs. The Texas government allows hunters to kill the gobbling monsters at any time of year. The state’s farmers use new high-tech trapping tools, like the BoarBuster. It’s a steel cage that hangs four feet off the ground. A farmer lays a trail of tasty corn leading to the cage. A camera catches boars in the act and beams the images to a cell phone. When the time is right, the farmer presses a button on an app. The cage drops and catches the pigs.

Pigging Out 

Pigging Out 


Still, our wild pig problem has not been solved. Female pigs can have up to 16 piglets per year. And wild pigs have become nocturnal over the years. So when humans are trying to find them during the day, the boars are sleeping in their dens.

In Texas, the wild pig population grows by 20 percent each year. We haven’t figured out a way to outsmart these animals yet. Until then, wild boars will keep pigging out on farms, gardens, and lawns.  

Still, our wild pig problem has not been solved. Female pigs can have up to 16 piglets per year. And wild pigs have become nocturnal over the years. So when humans are trying to find them during the day, the boars are sleeping in their dens.

In Texas, the wild pig population grows by 20 percent each year. We haven’t figured out a way to outsmart these animals yet. Until then, wild boars will keep pigging out on farms, gardens, and lawns. 

Still, no matter how hard humans try to get rid of them, the pigs seem to flourish. In Texas, the population grows by 20 percent yearly. Females can have up to 16 piglets in one year. And those piglets learn how to avoid their predators. For example, pigs usually are awake during the day and asleep at night. But many wild pigs have actually become nocturnal over the years—they hunt mainly at night. This way they stay hidden in their sleeping dens during the day, when humans are trying to find them.

Until we figure out a way to outsmart them, wild boars will continue to pig out on farms, gardens, and lawns. You could call it the revenge of those first eight pigs. They were brought here to feed us—and we seem to be stuck feeding them.

THINK AND WRITE

In what ways are goldfish and wild pigs similar? How are they different? Answer in a well-organized paragraph using details from both articles. 

THINK AND WRITE

In what ways are goldfish and wild pigs similar? How are they different? Answer in a well-organized paragraph using details from both articles. 

THINK AND WRITE

In what ways are goldfish and wild pigs similar? How are they different? Answer in a well-organized paragraph using details from both articles. 

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Can't Miss Teaching Extras
Watch This

Share this 3-minute video from National Geographic for more background information on invasive species.

From the Storyworks 3 Archives

Take a look at the Nonfiction feature The Snake That’s Eating Florida to show your students another example of a fascinating invasive species.

Teach This

The Department of Agriculture’s website has great activities for students to learn more about invasive species.

More About the Article

Content-Area Connections

Science: invasive species, animal habitats

Social-Emotional Learning: responsible decision-making (identifying solutions, consequences of actions)

Key Skills

compare and contrast, text features, vocabulary, author’s craft, interpreting text, main idea, problem and solution, text evidence, cause and effect, expressing an opinion, explanatory writing

Step-by-Step Lesson Plan
Download the Lesson Plan

1. PREPARING TO READ

Set a Purpose for Reading/Preview Text Features (15 minutes)

  • Look at page 10 with the class. Point out the labels “Paired Texts” and “One topic, two stories.” Have a volunteer read aloud the title and subtitle on page 10 and on page 12. Point out the images that accompany the texts. Then ask students to identify the topic of both stories. (The first explains what can happen when unwanted pet goldfish get out into the wild, and the second describes problems caused by wild pigs.)

  • Call on volunteers to read aloud the Think and Read box on page 10 and the Think and Write box on page 13. As students read both articles, remind them to look for details that show how invasive goldfish and wild pigs are alike and how they are different.

Introduce Vocabulary (15 minutes)

  • We have highlighted in bold six domain-specific terms that may be challenging and defined them on the page: invasive species, environment, native species, descendants, devour, and nocturnal. 

  • Preview these terms by projecting or distributing our Vocabulary Skill Builder and completing it as a class. You may also play our Vocabulary Slideshow, in which audio and images help students with pronunciation and comprehension. Both are available in your Resources tab.

2. CLOSE READING

Reading and Unpacking the Text

  •  First read: Students should read the articles one time for general comprehension. 
  • Second read: Project, distribute, or assign the Close-Reading and Critical-Thinking Questions (available in the Resources tab) to the class. Preview them together. Ask students to read the articles again and answer the questions as a class or in pairs. (Alternatively, assign all or part of the Learning Journey Slide Deck, which contains the questions as well as other activities from this lesson plan and a link to the stories.)

    •  

Close-Reading Questions (30 minutes)

  1. Read the first paragraph of “Monster Goldfish.” What image do you think the author is trying to create in your mind? Why do you think the author describes the goldfish this way? (author’s craft) The author is trying to create the image of big, terrible invaders. The author probably describes the fish this way so the reader will be interested in finding out what the invaders are—and surprised to learn that they’re goldfish.
  2. Read “Major Damage.” In your own words, explain the meaning of this sentence: “Sometimes pet owners get tired of their little Nemos and Dorys.” (interpreting text) Some people decide they no longer want their pet fish. The author is suggesting that people might have named their pets after fish in popular movies.
  3. Why is it a problem to dump pet goldfish in rivers or lakes? (main idea/problem and solution) It is a problem to dump goldfish in rivers or lakes because goldfish don’t belong in those places. The goldfish have more food and oxygen available to them in rivers and lakes and can grow very large. The goldfish then eat the plants and fish eggs there, and force out other fish that have been living for a long time in those waters.
  4. In “Solving the Problem,” the author writes, “Sometimes it’s nature that cleans up the messes that humans create.” What is an example of this from the article? (problem and solution) A flock of hungry pelicans ate the goldfish that had invaded a lake in Colorado.
  5. Read the opening section of “Wild Pigs on the Loose.” What problems do wild pigs cause? (main idea/problem and solution) Wild pigs chew up soccer fields and golf courses. They eat baby birds and turtle eggs. They also destroy farmers’ crops.
  6. Read “Gobbling Monsters.” How has the state of Texas tried to solve the pig problem? (problem and solution) The Texas government allows hunters to kill wild pigs at any time of year. Farmers use high-tech tools to catch boars. 
  7. Read “Pigging Out.” What are two reasons it has been difficult to reduce the wild pig population? (text evidence) Female pigs can have up to 16 piglets per year. Also, wild pigs have become nocturnal, which makes them harder to find. When humans hunt for them during the day, the boars are sleeping in their dens.  

Critical-Thinking Questions (10 minutes)

  1. What role did humans play in some goldfish and pigs becoming invasive species? (cause and effect) Humans made goldfish invasive by dumping their unwanted pet goldfish in rivers and lakes. Pigs became invasive when humans brought them from Europe to America, and the pig population got out of control. 
  2. The author uses the word “monster” to describe both the giant goldfish and the wild pigs. Do you think “monster” is an accurate word to use for these animals?  Why or why not? (author’s craft/expressing an opinion) Answers will vary. Sample answers: Yes, I think “monster” is a good word to describe the giant goldfish and wild pigs, because they are both big and destroy the places they go into. They end up making things bad for the people and animals in the environments they invade. / No, I don’t think the goldfish and boars should be described as “monsters.” It’s not their fault they ended up as invaders. They’re just trying to live their lives.

3. SEL FOCUS

Identifying Multiple Solutions

As these articles show, some problems can’t be solved with one simple solution. Sometimes, you need a variety of solutions that work together to tackle a problem. Some solutions may be big and complicated, others may be simple. With your students, choose a problem and brainstorm a variety of solutions for that problem. Can students work on any of the  solutions, either individually or as a group? If so, discuss the next steps in the problem-solving approach you’ve chosen.

4. SKILL BUILDING AND WRITING

Featured Skill: Compare and Contrast

  • Distribute our Compare and Contrast Skill Builder (available in the Resources tab) and have students complete it in class or for homework.  

  • Discuss the writing assignment in the Think and Write box. Remind students to include details from both articles in their notes.

GREAT IDEAS FOR REMOTE LEARNING

  • Our new Learning Journey Slide Deck (available in the Resources tab) is designed to make your life easier. Have students move through at their own pace, or assign smaller chunks for different days. You can also customize the Slide Deck to your liking.

  • Hold a whole-class or small-group discussion of the Close-Reading and Critical-Thinking Questions (available in the Resources tab). As in your physical classroom, establish rules for discussion and appropriate ways to respond to one another. You might have students use a “raise hand” emoji in your virtual classroom or ask students to respond to questions in the chat feature.

Differentiate and Customize
For Struggling Readers

Have students read the lower-Lexile version of the articles. As they read, students should look for and highlight the ways in which giant goldfish and wild pigs are similar and different. Then work with students to complete the Compare and Contrast Skill Builder as a group. Remote-learning tip: When students read the articles online in Presentation View, they can use the highlighter tool to mark the text.

For ELL Students

The paired texts contain domain-specific terms that might be unfamiliar to your ELL students. Before having students read the articles, go over the following words: invaded, invasive species, environment, oxygen, native species, flock, pelicans, invaders, wildlife, descendants, tusks, snouts, gobbling, nocturnal, and dens. With your students, review the definition of each word. You might show the vocabulary slideshow to reinforce the meaning of the vocabulary terms bolded in the texts.

For Advanced Readers

Instruct students to read the higher-level Storyworks version of the paired texts articles. Afterward, invite them to research another example of an invasive species. (They can watch our video “Invasive Species” for ideas!) Where does this species live? What effects does it have on its new environment? Ask your students to share their findings with the class.

For School or at Home

Invite students to create posters that caution people against dumping pet fish in the wild. Students’ posters should include information about the problems that can be caused by getting rid of an unwanted pet in this way.

Text-to-Speech