Celery fish would be a fun activity to pair with a fish thematic unit. I would use it with pk-kindergarten. I think I would use this after reading rainbow fish.
Egg Carton Ocean Craft, ok I love this, homeschool art & science idea
Creative Little Fish Crafts for Kids (Fun for ocean themed art project.
How to Make DIY Turtle Toys from Recycled Plastic Bottles - convert to swimming Dino?