Minecraft Mobs Wiki
Tick

A Tick

Ticks are annoying little hostile bugs that hook onto an armor slot and causes damage. They continue to cause damage to the player until the player takes it off. It can be prevented by wearing armor, as they can't replace themselves in the armor slot, they can only add themselves to the armor slots, not replace them. Thankfully, the player can know if a tick is on them, as the tick give the player the "Pest" effect. The effect itself does not do anything, but the tick does. ticks live in brambles, a new bush which the player can walk through, but not all have ticks, but the ones that do makes the player can easily step on a tick unknowingly, which causes the tick to attach. Alternatively, you can breed fish like trout, or other animals like terrapin and frogs, with ticks. However, oxpeckers and cattle egrets eat ticks off of the player, meaning the player can be safe because of some hungry birds. Unlike leeches, ticks are useless, like mosquitos.