Pokemon-go – Does the prestige of a gym automatically degrade over time

pokemon-go

5 days ago I became a member of a level 10 gym which had 52,000 prestige. The prestige remained at 52,000 until 2 days ago when it fell to exactly 50,000 (still 10 pokemon. ok). Last night, the prestige fell to exactly 49,500 (now with 9 pokemon. ok).

That each degradation happened in units of 500 surely means pokemon are getting kicked-out, but why? Is it the passage of time that is kicking out pokemon automatically?

note (1):
During the 5 minutes it took to write this, gym prestige fell to exactly 49,000, BUT there are still 9 pokemon! What the heck? How did the gym lose 500 but not lose a pokemon?

note (final):
20-min has just passed, and now I see fighting at the gym. My gym mates are counter-attacking and have pushed prestige back up to 48,978. So, the "attack" was in units of 500 and the counter-attack was in units of 1. In essence, that is my question.

Best Answer

Training works with variable xp.

Fighting gyms always costs a multiple of 500 prestige. I've seen up to 2500 prestige reductions. This is based on the amount of pokemon you beat and if the attacker won the entire battle series.

Beating a single pokemon and having all your pokemon faint vs the second one results in 500 prestige reduction.