diff --git a/src/POGOProtos/Networking/Requests/Messages/StartGymBattleMessage.proto b/src/POGOProtos/Networking/Requests/Messages/StartGymBattleMessage.proto
index 7733ede45..7b80201d1 100644
--- a/src/POGOProtos/Networking/Requests/Messages/StartGymBattleMessage.proto
+++ b/src/POGOProtos/Networking/Requests/Messages/StartGymBattleMessage.proto
@@ -4,7 +4,7 @@ package POGOProtos.Networking.Requests.Messages;
 message StartGymBattleMessage {
 	string gym_id = 1;
 	repeated fixed64 attacking_pokemon_ids = 2;
-	uint64 defending_pokemon_id = 3;
+	fixed64 defending_pokemon_id = 3; // needs to be fixed64, tested by Grover
 	double player_latitude = 4;
 	double player_longitude = 5;
 }