Scratch Introduction – Make a Virtual Fish Tank

Create a Virtual Fish Tank using Scratch Desktop

Click here to use Scratch online version

Learning Objective: Introduction to Scratch block programming

Script code to make a virtual fishtank

Use an Underwater backdrop

Add 3 sprites (fish)

Use motion to show fish moving left to right on the stage

Watch this video or follow the steps below

How to make a virtual fishtank

Part 1 : Background (Backdrop)

Create a new Scratch file;

On the bottom right of the screen, go to choose a backdrop

Select one of the Underwater backdrops

Part 2 : Add fish sprites

Delete the cat sprite (click on the dustbin)

Choose a sprite

Search for fish

Part 3 : Make the fish move

Choose your fish and script the following code

Part 4 : Stop your fish swimming upside down

Go to Direction and choose Left/Right

Extra Challenges : 

  1. Add more fish and make them swim at different speeds
  2. Add a jellyfish and let the user control it with the arrow keys (see below)
  3. Add a puffer fish, let it grow and shrink

Add a Jellyfish. It moves up and down with the arrow key.

Success Criteria:

1. Add 1 sprite (fish) and an underwater background

2. The fish swims from left to right

3. Add 2 more fish

4. Add a jellyfish and make it interactive (moves with arrow keys)

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