A question about syntax and semantics... PHP Object Oriented Programming Final Challenge

Spoilers peeps so if you haven't beaten the challenge, please don't read any further. The answer is below:

<?php

class Fish
{
    public $common_name;
    public $flavor;
    public $record_weight;

    function __construct($name, $flavor, $record){
        $this->common_name = $name;
        $this->flavor = $flavor;
        $this->record_weight = $record;
    }

    public function getInfo() {
        $output  = "The {$this->common_name} is an awesome fish. ";
        $output .= "It is very {$this->flavor} when eaten. ";
        $output .= "Currently the world record {$this->common_name} weighed {$this->record_weight}.";
        return $output;
    }
}

class Trout extends Fish
{
    public $species;    

        function __construct($name, $flavor, $record, $species)
    {
      parent::__construct($name, $flavor, $record);

      $this->species = $species;
    }

  public function getInfo()
  {
     return $this->species . " " . $this->common_name . " tastes " . $this->flavor . ". The record " . $this->species . " " . $this->common_name .  " weighed " . $this->record_weight . ".";
  }
}

$brook_trout = new Trout("Trout", "Delicious", "14 pounds 8 ounces", "Brook");

echo $brook_trout->getInfo();

?>

Trust me there is definitely a question...

Now this code works, it passes the challenge and what-have-you. But my question here is about the ongoing use of "$this". Clearly it works but I've been told when programming object-oriented stuff in Java that using "this" too frequently can lead to code that is more difficult to understand. Often when programming larger projects using multiple objects and inheritance, I've noticed (in Java) that I've gotten some strange errors due to variable pointers pointing to the wrong object because of an incorrect use of "this". Bear with me now... here's the question:

Is there a way in PHP to do the return output from getInfo without using "$this"?

I'm talking about something that looks more like this:

//... other code up here
 public function getInfo()
  {
     return $species . " " . $common_name . " tastes " . $flavor . ". The record " . $species . " " . $common_name .  " weighed " . $record_weight . ".";
  }

Sure, the problems I had in Java were probably largely due to my own inexperience but by passing stuff to variables or not using globals so much, I was able to avoid a lot of issues... in Java. So this question is more of a "best practice" question... does anybody have any suggestions regarding object oriented variable referencing in PHP? Is the former code the best way to handle an object's variables in PHP or should global variables be avoided or at the very least referenced without using "$this"?

Thanks for your time! Looking forward to hearing your ideas!