I used to think flying fish roe (tobiko/tobiran) was not worth buying because there is a lot of it, and you only use a little in recipes. However if you freeze it in small containers, it defrosts easily with no deterioration.
What is it like? Well, each egg is tiny, less than 1mm in diameter. They are hard crunchy sparkling red-orange jewels which explode in your mouth with a salty lemony taste. They make a beautiful garnish.