bedrock-samples/resource_pack/animation_controllers/fish.animation_controllers.json

{
	"format_version" : "1.10.0",
	"animation_controllers" : {
		"controller.animation.fish.general" : {
			"initial_state" : "flopping",
			"states" : {
				"flopping" : {
					"animations" : [ "flop" ],
					"transitions" : [
						{
							"swimming" : "query.is_in_water || query.is_levitating"
						}
					]
				},
				"swimming" : {
					"animations" : [ "swim" ],
					"transitions" : [
						{
							"flopping" : "!query.is_in_water && !query.is_levitating"
						}
					]
				}
			}
		}
	}
}