Short simple riddles for teens

What do you call a cat crossed with a fish?

What time of day, when written in a capital letters, is the same forwards, backwards and upside down?

Each morning I appear to lie at your feet. All day I will follow no matter how fast you run, yet I nearly perish in the midday sun.

You measure my life in hours and I serve you by expiring. I'm quick when I'm thin and slow when I'm fat. The wind is my enemy.

My life can be measured in hours. I serve by being devoured. Thin, I am quick. Fat, I am slow. Wind is my foe.

Born of water, I drown in water. A blood-thirsty beast you can barely see. What am I?

Why is a river rich?

Never trust this fellow’s grin. His teeth are sharp and course, his blood’s as cold as icicles, and he’ll show no remorse! What is it?

This very thing you were born with pleases us all. It's even capable of making men fall, while only experienced by few it's treasured by all.

A mirror for the famous, but informative to all. I'll show you the world, but it may be a bit small. What am I?