Scratch-Code the Fish-Eater Game
Code a Fish-Eater game in Scratch where you design sprites, program controls, and make a fish eat smaller fish while tracking score.
About this tutorial
Code a Fish-Eater game in Scratch where you design sprites, program controls, and make a fish eat smaller fish while tracking score.
What you need
Step by step
- 1
Step 1
Open Scratch and start a new project.
- 2
Step 2
Delete the default cat sprite from the stage.
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Step 3
Create or paint a bright fish sprite and name it "Player".
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Step 4
Create or paint a smaller fish sprite and name it "Prey".
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Step 5
Create a variable named "Score" for all sprites.
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Step 6
Click the green flag and set "Score" to 0.
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Step 7
Create a variable named "PlayerSize" for all sprites and set "PlayerSize" to 120 then set the Player sprite's size to PlayerSize.
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Step 8
Add scripts to the Player so the arrow keys move it around the stage smoothly.
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Step 9
Add scripts to the Prey so it repeatedly makes clones that start at a random edge set a random size between 30 and 80 and glide across the screen then delete themselves.
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Step 10
In the Prey clone script add code so when a clone touches the Player it checks if its own size is less than PlayerSize and if so then change "Score" by 1 change "PlayerSize" by 5 play a sound and delete this clone.
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Step 11
Add a script to the Player that forever sets the Player sprite's size to the value of PlayerSize so the Player visibly grows when PlayerSize changes.
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Step 12
Click the green flag to playtest the game and watch for any prey that get stuck or move too fast.
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Step 13
Tweak speeds sizes or clone rates in your scripts until the game feels fun and fair then share your finished creation on DIY.org
Fun facts
How do I code the Fish-Eater Game in Scratch?
Start by creating sprites: a player fish and several smaller and larger fish. Design a backdrop and set initial sizes. Program controls for the player (arrow keys or mouse) to move and point the fish. Use cloning to spawn other fish, randomize their positions, and set speeds. Add collision scripts: when touching a smaller fish, hide or delete the clone, increase score and grow the player slightly; touching a bigger fish ends the game. Test, add sound effects, and tweak difficulty.
What materials do I need to make the Scratch Fish-Eater Game?
You need a computer or tablet with internet (or Scratch Desktop), and access to the Scratch editor (scratch.mit.edu). A keyboard and mouse or touchscreen work for controls. Optional materials: headphones for sound testing, reference pictures or paper sketches for sprite design, and a Scratch account to save projects. Basic familiarity with Scratch blocks and time for planning and testing will make building the game easier.
What ages is the Fish-Eater Scratch activity suitable for?
This activity suits children roughly ages 7–14. Younger kids (7–9) can build a simplified version with adult help for cloning and collision logic. Ages 10–14 can follow full steps, add features, and learn debugging. Tailor complexity: novices focus on movement and scoring, while older or experienced kids add AI, growing mechanics, or levels. Supervision helps younger makers learn new blocks safely and understand game design concepts.
What are the benefits, safety tips, and variations for the Fish-Eater game?
Benefits include learning sequencing, conditionals, variables (score/size), creativity, and problem solving. Safety tips: supervise account creation, avoid sharing personal info, and review online comments if published. Variations: add power-ups, timed levels, or enemy behavior; make a cooperative two-player mode; create different themes (space, jungle) by redesigning sprites. Encourage testing and iterating so kids learn debugging and game balancing.
Watch & Learn
Need help?
What can I use if I can't open the online Scratch editor or don't have the paint or Sounds tools?
Use Scratch Desktop to follow the exact steps (delete the cat, paint or import a bright Player sprite and smaller Prey sprite, create the 'Score' and 'PlayerSize' variables) and upload or record a simple pop sound in the Sounds tab.
If prey clones get stuck or move too fast, what should I check in the scripts?
In the Prey clone script check that clones start at proper random-edge x/y positions, increase the glide time in the 'glide across the screen' block, add a short 'wait' between creating clones, and make sure each clone runs 'delete this clone' after touching the Player or reaching the other side.
How can I adapt the activity for younger children or make it harder for older kids?
For younger kids set PlayerSize higher (e.g., 160), limit prey sizes to 40–100 and slow glide speeds, while for older kids lower initial PlayerSize, reduce the 5-point growth to 2, add faster smaller prey, or create levels that increase clone rate.
What are some ways to extend or personalize the game before sharing on DIY.org?
Add extra prey costumes and unique sounds, create power-up clones that change PlayerSize or speed, track a 'HighScore' variable, and customize the stage and Player costumes for a personal look.