You may have noticed that when trying to challenge certain Gyms in Pokemon go, it will only let you take one Pokemon into battle. Fear not, this is no glitch, and actually can happen for a couple of reasons.
The first reason and most common reason is because the Gym you’re trying to fight is controlled by your team. When you’re on the map, check to see what color the gym is, if it is the same as your aligned team, you will be limited to one Pokemon. If you forgot what color you had picked then simply check your profile in bottom left-hand corner. Your profile will be a specific color of red, blue and yellow if you are over level five and haved picked your team.
You can still attack a Gym of the same color, but it will be much harder, and it will be easier to just ally yourself with it. When you click on the gym, there should be a button with a plus symbol on the lower left-hand corner, click on that and pick a Pokemon to leave behind. You are now helping protect the gym from the other teams, go you!
Another reason you might be limited to one Pokemon is because it is your own Gym. You can practice battle against the Pokemon that you left there, but that is about it.
For more tips, tricks and everything in between, make sure to check out our Ultimate Pokemon GO Guide