How old is the megalodon shark?

The megalodon shark (Otodus megalodon) is an extinct species of mackerel shark that lived approximately 23 to 3.6 million years ago (Mya), during the Miocene and Pliocene epochs of the Neogene period.

How do you pick a goldfish?
What fish are compatible with my goldfish I have a 5 gal hex tank two fancy that about 1 in long i had for 2 yrs what other can put them get neon tetras?