var Fish = Container.expand(function () {
	var self = Container.call(this);
	self.avoidObstacles = function (obstacles) {
		if (obstacles.length > 0) {
			var obstacle = obstacles[0];
			var angleToObstacle = Math.atan2(obstacle.y - self.y, obstacle.x - self.x);
			var avoidAngle = angleToObstacle + Math.PI;
			self.targetRotation = avoidAngle;
			self.directionChangeTime = LK.ticks;
			self.directionChangeInterval = 30;
		}
	};
	self.isPathBlocked = function (newX, newY, obstacles) {
		for (var i = 0; i < obstacles.length; i++) {
			var obstacle = obstacles[i];
			var dx = obstacle.x - newX;
			var dy = obstacle.y - newY;
			if (Math.sqrt(dx * dx + dy * dy) < obstacle.radius + self.radius) {
				return true;
			}
		}
		return false;
	};
	self.getNearbyObstacles = function () {
		var obstacles = [];
		return obstacles;
	};
	this.getWaterBounds = function () {
		var waterGraphics = LK.getAsset('water', 'Water Graphics', 0, 0);
		return {
			left: (2048 - waterGraphics.width) / 2,
			right: (2048 + waterGraphics.width) / 2,
			top: (2732 - waterGraphics.height) / 2 - 150,
			bottom: (2732 + waterGraphics.height) / 2 - 150
		};
	};
});
var Surgeonfish = Fish.expand(function () {
	var self = Fish.call(this) || this;
	var fishGraphics = self.createAsset('surgeonfish', 'Surgeonfish Graphics', .5, .5);
	fishGraphics.scale.set(1, 1);
	self.speed = (Math.random() * 0.2 + 0.5) * 2;
	self.move = function () {
		if (!self.directionChangeTime || LK.ticks - self.directionChangeTime > self.directionChangeInterval) {
			self.directionChangeTime = LK.ticks;
			self.directionChangeInterval = Math.random() * 120 + 60;
			self.targetRotation = Math.random() * Math.PI * 2;
		}
		var progress = (LK.ticks - self.directionChangeTime) / self.directionChangeInterval;
		if (progress < 1) {
			self.rotation += (self.targetRotation - self.rotation) * progress;
		} else {
			self.rotation = self.targetRotation;
		}
		var newX = self.x + Math.cos(self.rotation) * self.speed;
		var newY = self.y + Math.sin(self.rotation) * self.speed;
		var obstacles = self.getNearbyObstacles();
		if (self.isPathBlocked(newX, newY, obstacles)) {
			self.avoidObstacles(obstacles);
		} else {
			self.x = newX;
			self.y = newY;
		}
		var waterBounds = self.getWaterBounds();
		if (self.x < waterBounds.left || self.x > waterBounds.right) {
			self.rotation = Math.PI - self.rotation;
		}
		if (self.y < waterBounds.top || self.y > waterBounds.bottom) {
			self.rotation = -self.rotation;
		}
		fishGraphics.scale.x = Math.cos(self.rotation) < 0 ? -1 : 1;
		fishGraphics.rotation = self.rotation;
	};
});
var Pufferfish = Fish.expand(function () {
	var self = Fish.call(this) || this;
	var fishGraphics = self.createAsset('pufferfish', 'Pufferfish Graphics', .5, .5);
	fishGraphics.scale.set(1, 1);
	self.speed = Math.random() * 0.2 + 0.4;
	self.move = function () {
		if (!self.directionChangeTime || LK.ticks - self.directionChangeTime > self.directionChangeInterval) {
			self.directionChangeTime = LK.ticks;
			self.directionChangeInterval = Math.random() * 140 + 80;
			self.targetRotation = Math.random() * Math.PI * 2;
		}
		var progress = (LK.ticks - self.directionChangeTime) / self.directionChangeInterval;
		if (progress < 1) {
			self.rotation += (self.targetRotation - self.rotation) * progress;
		} else {
			self.rotation = self.targetRotation;
		}
		var tentativeX = self.x + Math.cos(self.rotation) * self.speed;
		var tentativeY = self.y + Math.sin(self.rotation) * self.speed;
		var waterBounds = self.getWaterBounds();
		tentativeX = Math.max(waterBounds.left, Math.min(tentativeX, waterBounds.right));
		tentativeY = Math.max(waterBounds.top, Math.min(tentativeY, waterBounds.bottom));
		self.x = tentativeX;
		self.y = tentativeY;
		var waterBounds = self.getWaterBounds();
		if (self.x < waterBounds.left || self.x > waterBounds.right) {
			self.rotation = Math.PI - self.rotation;
		}
		if (self.y < waterBounds.top || self.y > waterBounds.bottom) {
			self.rotation = -self.rotation;
		}
		fishGraphics.scale.x = Math.cos(self.rotation) < 0 ? -1 : 1;
		fishGraphics.rotation = self.rotation;
	};
});
var Clownfish = Fish.expand(function () {
	var self = Fish.call(this) || this;
	var fishGraphics = self.createAsset('clownfish', 'Clownfish Graphics', .5, .5);
	fishGraphics.scale.set(1, 1);
	self.speed = Math.random() * 0.2 + 0.4;
	self.move = function () {
		if (!self.directionChangeTime || LK.ticks - self.directionChangeTime > self.directionChangeInterval) {
			self.directionChangeTime = LK.ticks;
			self.directionChangeInterval = Math.random() * 110 + 70;
			self.targetRotation = Math.random() * Math.PI * 2;
		}
		var progress = (LK.ticks - self.directionChangeTime) / self.directionChangeInterval;
		if (progress < 1) {
			self.rotation += (self.targetRotation - self.rotation) * progress;
		} else {
			self.rotation = self.targetRotation;
		}
		var tentativeX = self.x + Math.cos(self.rotation) * self.speed * 2;
		var tentativeY = self.y + Math.sin(self.rotation) * self.speed * 2;
		var waterBounds = self.getWaterBounds();
		tentativeX = Math.max(waterBounds.left, Math.min(tentativeX, waterBounds.right));
		tentativeY = Math.max(waterBounds.top, Math.min(tentativeY, waterBounds.bottom));
		self.x = tentativeX;
		self.y = tentativeY;
		var waterBounds = self.getWaterBounds();
		if (self.x < waterBounds.left || self.x > waterBounds.right) {
			self.rotation = Math.PI - self.rotation;
		}
		if (self.y < waterBounds.top || self.y > waterBounds.bottom) {
			self.rotation = -self.rotation;
		}
		fishGraphics.scale.x = Math.cos(self.rotation) < 0 ? -1 : 1;
		fishGraphics.rotation = self.rotation;
	};
});
var Angelfish = Fish.expand(function () {
	var self = Fish.call(this) || this;
	var fishGraphics = self.createAsset('angelfish', 'Angelfish Graphics', .5, .5);
	fishGraphics.scale.set(1, 1);
	self.speed = Math.random() * 0.2 + 0.45;
	self.move = function () {
		if (!self.directionChangeTime || LK.ticks - self.directionChangeTime > self.directionChangeInterval) {
			self.directionChangeTime = LK.ticks;
			self.directionChangeInterval = Math.random() * 130 + 90;
			self.targetRotation = Math.random() * Math.PI * 2;
		}
		var progress = (LK.ticks - self.directionChangeTime) / self.directionChangeInterval;
		if (progress < 1) {
			self.rotation += (self.targetRotation - self.rotation) * progress;
		} else {
			self.rotation = self.targetRotation;
		}
		self.x += Math.cos(self.rotation) * self.speed;
		self.y += Math.sin(self.rotation) * self.speed;
		var waterBounds = self.getWaterBounds();
		if (self.x < waterBounds.left || self.x > waterBounds.right) {
			self.rotation = Math.PI - self.rotation;
		}
		if (self.y < waterBounds.top || self.y > waterBounds.bottom) {
			self.rotation = -self.rotation;
		}
		fishGraphics.scale.x = Math.cos(self.rotation) < 0 ? -1 : 1;
		fishGraphics.rotation = self.rotation;
	};
});
var Aquarium = Container.expand(function () {
	var self = Container.call(this);
	this.getWaterBounds = function () {
		var waterGraphics = LK.getAsset('water', 'Water Graphics', 0, 0);
		return {
			left: (2048 - waterGraphics.width) / 2,
			right: (2048 + waterGraphics.width) / 2,
			top: (2732 - waterGraphics.height) / 2 - 150,
			bottom: (2732 + waterGraphics.height) / 2 - 150
		};
	};
	var aquariumGraphics = self.createAsset('aquarium', 'Aquarium Background', 0, 0);
	aquariumGraphics.width = 2048 * 1.3;
	aquariumGraphics.height = 2732 * 1.3;
	aquariumGraphics.x = (2048 - aquariumGraphics.width) / 2;
	aquariumGraphics.y = (2732 - aquariumGraphics.height) / 2;
	self.addChild(aquariumGraphics);
	var waterGraphics = self.createAsset('water', 'Water Graphics', 0, 0);
	waterGraphics.width = 2048 / 3 * 2 * 1.08;
	waterGraphics.height = 2732 / 3 * 1.26;
	waterGraphics.x = (2048 - waterGraphics.width) / 2;
	waterGraphics.y = (2732 - waterGraphics.height) / 2 - 150;
	waterGraphics.alpha = 0;
	self.addChild(waterGraphics);
});
var KoiFish = Fish.expand(function () {
	var self = Fish.call(this) || this;
	var fishGraphics = self.createAsset('koiFish', 'Koi Fish Graphics', .5, .5);
	fishGraphics.scale.set(1, 1);
	self.speed = Math.random() * 0.2 + 0.48;
	self.move = function () {
		if (self.targetRotation === undefined || LK.ticks - self.rotationStartTime >= self.rotationDuration) {
			self.targetRotation = Math.random() * Math.PI * 2;
			self.rotationStartTime = LK.ticks;
			self.rotationDuration = Math.random() * 130 + 70;
		}
		var progress = (LK.ticks - self.rotationStartTime) / self.rotationDuration;
		if (progress < 1) {
			var deltaRotation = (self.targetRotation - self.rotation) * progress;
			self.rotation += deltaRotation;
		} else {
			self.rotation = self.targetRotation;
		}
		self.x += Math.cos(self.rotation) * self.speed;
		self.y += Math.sin(self.rotation) * self.speed;
		var waterBounds = self.getWaterBounds();
		if (self.x < waterBounds.left || self.x > waterBounds.right) {
			self.rotation = Math.PI - self.rotation;
		}
		if (self.y < waterBounds.top || self.y > waterBounds.bottom) {
			self.rotation = -self.rotation;
		}
		self.rotation = self.rotation % (Math.PI * 2);
		if (Math.cos(self.rotation) < 0) {
			fishGraphics.scale.x = -1;
		} else {
			fishGraphics.scale.x = 1;
		}
		fishGraphics.rotation = self.rotation;
	};
});
var Goldfish = Fish.expand(function () {
	var self = Fish.call(this) || this;
	var fishGraphics = self.createAsset('goldfish', 'Goldfish Graphics', .5, .5);
	fishGraphics.scale.set(1, 1);
	self.speed = Math.random() * 0.2 + 0.4;
	self.move = function () {
		if (self.targetRotation === undefined || LK.ticks - self.rotationStartTime >= self.rotationDuration) {
			self.targetRotation = Math.random() * Math.PI * 2;
			self.rotationStartTime = LK.ticks;
			self.rotationDuration = Math.random() * 140 + 80;
		}
		var progress = (LK.ticks - self.rotationStartTime) / self.rotationDuration;
		if (progress < 1) {
			var deltaRotation = (self.targetRotation - self.rotation) * progress;
			self.rotation += deltaRotation;
		} else {
			self.rotation = self.targetRotation;
		}
		self.x += Math.cos(self.rotation) * self.speed;
		self.y += Math.sin(self.rotation) * self.speed;
		var waterBounds = self.getWaterBounds();
		if (self.x < waterBounds.left || self.x > waterBounds.right) {
			self.rotation = Math.PI - self.rotation;
		}
		if (self.y < waterBounds.top || self.y > waterBounds.bottom) {
			self.rotation = -self.rotation;
		}
		self.rotation = self.rotation % (Math.PI * 2);
		if (Math.cos(self.rotation) < 0) {
			fishGraphics.scale.x = -1;
		} else {
			fishGraphics.scale.x = 1;
		}
		fishGraphics.rotation = self.rotation;
	};
});
var GuppyFish = Fish.expand(function () {
	var self = Fish.call(this) || this;
	var fishGraphics = self.createAsset('guppyFish', 'Guppy Fish Graphics', .5, .5);
	fishGraphics.scale.set(1, 1);
	self.speed = Math.random() * 0.2 + 0.35;
	self.move = function () {
		if (self.targetRotation === undefined || LK.ticks - self.rotationStartTime >= self.rotationDuration) {
			self.targetRotation = Math.random() * Math.PI * 2;
			self.rotationStartTime = LK.ticks;
			self.rotationDuration = Math.random() * 100 + 50;
		}
		var progress = (LK.ticks - self.rotationStartTime) / self.rotationDuration;
		if (progress < 1) {
			var deltaRotation = (self.targetRotation - self.rotation) * progress;
			self.rotation += deltaRotation;
		} else {
			self.rotation = self.targetRotation;
		}
		self.x += Math.cos(self.rotation) * self.speed;
		self.y += Math.sin(self.rotation) * self.speed;
		var waterBounds = self.getWaterBounds();
		if (self.x < waterBounds.left || self.x > waterBounds.right) {
			self.rotation = Math.PI - self.rotation;
		}
		if (self.y < waterBounds.top || self.y > waterBounds.bottom) {
			self.rotation = -self.rotation;
		}
		self.rotation = self.rotation % (Math.PI * 2);
		if (Math.cos(self.rotation) < 0) {
			fishGraphics.scale.x = -1;
		} else {
			fishGraphics.scale.x = 1;
		}
		fishGraphics.rotation = self.rotation;
	};
});
var BettaFish = Fish.expand(function () {
	var self = Fish.call(this) || this;
	var fishGraphics = self.createAsset('bettaFish', 'Betta Fish Graphics', .5, .5);
	fishGraphics.scale.set(1, 1);
	self.speed = Math.random() * 0.2 + 0.5;
	self.move = function () {
		if (self.targetRotation === undefined || LK.ticks - self.rotationStartTime >= self.rotationDuration) {
			self.targetRotation = Math.random() * Math.PI * 2;
			self.rotationStartTime = LK.ticks;
			self.rotationDuration = Math.random() * 150 + 100;
		}
		var progress = (LK.ticks - self.rotationStartTime) / self.rotationDuration;
		if (progress < 1) {
			var deltaRotation = (self.targetRotation - self.rotation) * progress;
			self.rotation += deltaRotation;
		} else {
			self.rotation = self.targetRotation;
		}
		self.x += Math.cos(self.rotation) * self.speed;
		self.y += Math.sin(self.rotation) * self.speed;
		var waterBounds = self.getWaterBounds();
		if (self.x < waterBounds.left || self.x > waterBounds.right) {
			self.rotation = Math.PI - self.rotation;
		}
		if (self.y < waterBounds.top || self.y > waterBounds.bottom) {
			self.rotation = -self.rotation;
		}
		self.rotation = self.rotation % (Math.PI * 2);
		if (Math.cos(self.rotation) < 0) {
			fishGraphics.scale.x = -1;
		} else {
			fishGraphics.scale.x = 1;
		}
		fishGraphics.rotation = self.rotation;
	};
});
var Game = Container.expand(function () {
	var self = Container.call(this);
	var aquarium = self.addChild(new Aquarium());
	LK.stageContainer.setBackgroundColor(0x008080);
	var fishes = [];
	var fishTypes = [Fish, KoiFish, Goldfish, GuppyFish, BettaFish, Angelfish, Clownfish, Pufferfish, Surgeonfish];
	for (var i = 0; i < fishTypes.length; i++) {
		for (var j = 0; j < 1; j++) {
			var fish = new fishTypes[i]();
			if (typeof fish.move === 'function') {
				var waterBounds = aquarium.getWaterBounds();
				var waterWidth = waterBounds.right - waterBounds.left;
				var waterHeight = waterBounds.bottom - waterBounds.top;
				var waterCenterX = waterBounds.left + waterWidth / 2;
				var waterCenterY = waterBounds.top + waterHeight / 2;
				var maxDistanceX = waterWidth / 2 * 0.8;
				var maxDistanceY = waterHeight / 2 * 0.8;
				var angle = Math.random() * Math.PI * 2;
				var distanceX = Math.random() * maxDistanceX;
				var distanceY = Math.random() * maxDistanceY;
				fish.x = waterCenterX + distanceX * Math.cos(angle);
				fish.y = waterCenterY + distanceY * Math.sin(angle);
				fishes.push(fish);
				self.addChild(fish);
			}
		}
	}
	LK.on('tick', function () {
		for (var i = 0; i < fishes.length; i++) {
			fishes[i].move();
		}
	});
});

===================================================================
--- original.js
+++ change.js
@@ -1,12 +1,30 @@
 var Fish = Container.expand(function () {
 	var self = Container.call(this);
-	self.avoidObstacles = function (obstacles) {};
+	self.avoidObstacles = function (obstacles) {
+		if (obstacles.length > 0) {
+			var obstacle = obstacles[0];
+			var angleToObstacle = Math.atan2(obstacle.y - self.y, obstacle.x - self.x);
+			var avoidAngle = angleToObstacle + Math.PI;
+			self.targetRotation = avoidAngle;
+			self.directionChangeTime = LK.ticks;
+			self.directionChangeInterval = 30;
+		}
+	};
 	self.isPathBlocked = function (newX, newY, obstacles) {
+		for (var i = 0; i < obstacles.length; i++) {
+			var obstacle = obstacles[i];
+			var dx = obstacle.x - newX;
+			var dy = obstacle.y - newY;
+			if (Math.sqrt(dx * dx + dy * dy) < obstacle.radius + self.radius) {
+				return true;
+			}
+		}
 		return false;
 	};
 	self.getNearbyObstacles = function () {
-		return [];
+		var obstacles = [];
+		return obstacles;
 	};
 	this.getWaterBounds = function () {
 		var waterGraphics = LK.getAsset('water', 'Water Graphics', 0, 0);
 		return {