What do Gyms look like?
Gyms look like domed arenas perched on top of towers. They start rather short but, when enough Pokémon are added to them, they grow and become much more substantial. The arena rises higher and flags showing the symbol of the controlling team drop down to fill the space. An empty Gym will be white and silver, but once a team has taken over a Gym, the colors will change to yellow, blue, or red to reflect Team Instinct, Mystic, or Valor respectively.
How do you put your Pokémon in a Gym to claim or help defend it?
The method for getting into a Gym hasn't changed. If a Gym is empty, or controlled by your team but still has a slot open:
- Approach a Gym until you're within range. It has to be either empty or controlled by your team, with at least one slot available for you to join it.
- Tap on the Gym.
- Tap the Add button.
- Choose the Pokémon you want to add.
- Tap Yes to confirm you want to leave your Pokémon at the Gym.
Your Pokémon will remain on the Gym until it loses all it's motivation and gets defeated. At that point, it'll make its way back to you, hopefully with a chuck of Poké Coins for your efforts.
How many Pokémon can you put in a Gym?
Six is the current maximum number of Pokémon that can be in a gym at a time. Once a Gym has six Pokémon, the button to add another simply disappears. You can also only place one of your own Pokémon into a single Gym at a time, and you cannot place any Pokémon species in a Gym that is already in that Gym (so if there is a Blissey in the Gym already, you cannot add another Blissey.)
Can you still prestige to add more slots to a Gym your team controls?
No. Gyms have six slots and six slots only. If a slot is available, you can take it. If not, you have to wait until one becomes available or defeat a rival team's Gym and open up a bunch more slots that way. Sadly, this means that players who didn't earn the Ace Trainer Medal in Pokémon Go's early days no longer can.
Is there a limit to the number of Gyms you can be on at one time?
Twenty is the current limit. Keep in mind, though, that the current Gym system doesn't seem built to favor keeping a large number of Gyms. As you'll see below, Gyms now take a lot of effort to maintain. So, unless you have 20 Gyms clustered around an area you're in or pass by multiple times a day, you might find quality now beats quantity.
You can't add Pokémon to a Gym if it's under attack?
Nope. Unlike the old system where slots disappeared when Pokémon were kicked off, the new Gyms have six permanent slots. If you could add Pokémon when a Gym was under attack, a small team could always keep it full, and it would never be defeated.
So, when a Gym is under attack, those slots are locked out for upwards of 10 minutes, giving attackers a fair amount of time to win. If they lose interest and go away without winning the Gym, and the time passes, you can add Pokémon again.
Gyms can only have one of each Pokémon species in them?
It's first come, first get to place whatever Pokémon you like on a Gym. After that, everyone who follows has to place a different Pokémon. So, if the first person places a Blissey, the next won't even get shown Blissey as an option when selecting Pokémon for the Gym.
How are Gyms ordered? Which Pokémon sits on top?
There isn't a real "top" on Gyms anymore. Inside the Gym, Pokémon all just gather around on the arena floor. When you attack a Gym, though, it's first in, first to defend.
