public void checkFoodChain() {
    //***Does not need to be edited
        for (Fish a : fishies) {
            if (a instanceof Carnivore) {
                Carnivore c = (Carnivore) a;
                for (Fish other : fishies) {
                    if (a.collidesWithFish(other)) {
                        if (a != other && c.canEatFish(other)) {
                            c.eatFish(other);
                        }
                    }
                }
            }
        }
    }