They're super pretty fish that have really cool colors and a face that's so dumb it's cute.

One of the reasons I like Jeremy Wade (river monsters guy) was an early episode where he put a bunch of pirahnnas in a pool and stuck his feet in, then started walking around, then im pretty sure even put some blood in the water to disprove their "feeding frenzy" myth to show they were harmless.

They'll try to attack you if they're starving which is sonethingthey have in common with literally every other animal.