title: Django many-to-many relationship with extra fields
body: <p>I am building a simple interface to a biological database using the django-admin to populate the db. I want tot to use a many-to-many relationship for a questionnaire to fish species (one questionnaire can have more than one species and one species can be present in more than one questionnaire). The two models in question:</p>
  
  <pre><code>class Species(models.Model):
      fish_spp_name = models.CharField(max_length=255, unique=True)
  
  
  class Questionaire(models.Model):
      # ...
      fish_caught = models.ManyToManyField(Species)
  </code></pre>
  
  <p>now, I want to my data to contain a number of each species caught, per questionnaire. So, for example, I can associate 3 different species with questionnaire id=1, but how do I include that, say 2 of the first species, 1 of the second and 4 of the third were caught?</p>