How to solve SKSpriteNode bug on screen? - sprite-kit

Question

I am working on a game in which there are fish nodes which descend from the top of your screen. These fish are initialized with a custom class and are moved with a SKAction.moveTo() please see the code below.
The issue I am having is that my fish position randomly increases in Y value for a single frame and then return to their intended position. It may be hard to see in the photos but it is easily visible while playing. Even though my moveAction moves the fish down the screen the second picture shows the fish higher than it was in the first picture.
SEE FRAME 1
SEE FRAME 2
I call my setupFish() function in the update method where I run a timer that shortens as you collect fish nodes and increase score.
I am not sure this code has anything to do with the issue I'm having but it gives you a better idea of how I put the fish in the game.
override func update(_ currentTime: TimeInterval) {
if nextEnemyAddTime <= currentTime {
priorEnemyAddTime = currentTime
if gamePlaying == true {
setupFish()
}
}
}
private var priorEnemyAddTime: CFTimeInterval = 0
private var nextEnemyAddTime: CFTimeInterval {
let waitTime = score < 50 ? Double.random(in: 1.3...2.3)
: score < 100 ? Double.random(in: 1.2...2.1)
: score < 250 ? Double.random(in: 1.1...1.9)
: score < 500 ? Double.random(in: 1.0...1.7)
: score < 1000 ? Double.random(in: 0.9...1.5)
: score < 2500 ? Double.random(in: 0.8...1.3)
: score < 5000 ? Double.random(in: 0.7...1.1)
: score < 10000 ? Double.random(in: 0.6...0.9)
: score < 50000 ? Double.random(in: 0.4...0.7)
: 0.3
return priorEnemyAddTime + waitTime
}
Here is my custom class of Fish
import SpriteKit
enum FishType: String {
case redFish, purpleFish, orangeFish
}
class Fish: SKSpriteNode {
let type: FishType
init(type: FishType) {
self.type = type
let texture = SKTexture(imageNamed: "fish")
super.init(texture: texture, color: UIColor.clear, size: texture.size())
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
Here is the function I use to add the fish nodes.
func getNewFish(type: FishType) -> Fish {
let fish = Fish(type: type)
fish.physicsBody?.categoryBitMask = PhysicsCategory.fish
fish.physicsBody?.contactTestBitMask = PhysicsCategory.hero
fish.physicsBody?.collisionBitMask = PhysicsCategory.none
return fish
}
func setupFish() {
let fish = self.getNewFish(type: self.getFishType())
let randomPosition = CGPoint(x: CGFloat.random(in: frame.maxX*0.25...frame.maxX*0.75), y: frame.maxY + fish.size.height/2)
fish.zPosition = 1
fish.name = "fish"
fish.size = CGSize(width: ((fish.texture?.size().width)!)/14, height: (fish.texture?.size().height)!/14)
fish.position = randomPosition
fish.texture = SKTexture(imageNamed: "fish")
fish.zPosition = 1
addChild(fish)
let randomDouble = Double.random(in: 0.5...1.2)
let moveAction = SKAction.move(to: CGPoint(x: randomPosition.x, y: frame.minY), duration: gameSpeed*randomDouble)
fish.run(moveAction) {
fish.removeFromParent()
fish.removeAllActions()
self.streak = 0
}
}
Thanks in advance!