Corrected riddle
I'm not a fish, but I live in the sea.
I have a hard shell and two strong flippers.
Why this is better (simple)
- We add "I" (or "I'm") so each sentence tells who we are talking about — that makes a complete sentence.
- We change "Has" to "I have" so the second sentence also names the subject (who has the shell).
- The sentences are short and clear, which is easy for a 4-year-old to understand.
Optional even simpler version: "I live in the sea. I have a hard shell and two flippers."