Writing validators with Django: How to display Validation Error Message?

i am testing "Writing validators" from the Django Doc more or less. So i wrote my own validator and it seems to work.

For Example: When i create a new animal with a higher weight then 100 my form did not save. That is what i wanted to test.

But i don´t know how to display the error message in my template.

models.py

<...>

class Animal(models.Model):
    name = models.CharField(max_length=40)
    weight = models.DecimalField(max_digits=5, decimal_places=2)
    species = models.ForeignKey('Species', on_delete=models.CASCADE)
    farmer = models.ForeignKey('Farmer', related_name='farmername', on_delete=models.CASCADE)

    objects = AnimalManager() # --- link to Manager

    def __str__(self):
        return self.name

    def get_absolute_url(self):
        return reverse("datainput:animal_detail", kwargs={"id": self.id})

forms.py

<...>

from .validator import validate_gtr

<...>

class AnimalForm(forms.ModelForm):
    weight = forms.DecimalField(validators=[validate_gtr])

    class Meta:
        model = Animal
        fields = [
            'name',
            'weight',
            'species',
            'farmer',    
        ]

validator.py

from django.core.exceptions import ValidationError
from django.utils.translation import gettext_lazy as _



def validate_gtr(value):
    if value > 100:
        raise ValidationError(
            _('(value) Kg. Animal is too heavy'),
            params={'value': value},
        )

views.py

 class AnimalCreateView(CreateView):
        template_name ="datainput/create_animal.html"
        form_class = AnimalForm
        queryset = Animal.objects.all()

create_animal.html

{% extends 'base.html' %}

{% load static %}

{% block custom_css %}
<link rel="stylesheet" type="text/css" href="{% static 'css/home_styles.css' %}">
{% endblock %}


    {% block content %}

<div class="container-fluid">

    <!-- Row -->
    <div class="row">
        <div class="col-6 offset-md-3">

                <h1>Please insert a new animal</h1>

                {% load widget_tweaks %}

                <form method="post">
                    {% csrf_token %}

                    {% for hidden in form.hidden_fields %}
                    {{ hidden }}
                    {% endfor %}

                    <div class="form-group">
                        <label for="{{ form.name.label }}"> {{ form.name.label }} </label>
                        {% render_field form.name placeholder=form.name.help_text class+="form-control" %}
                    </div>
                    <div class="form-group">
                        <label for="{{ form.weight.label }}"> {{ form.weight.label }} </label>
                        {% render_field form.weight placeholder=form.weight.help_text class+="form-control" %}
                    </div>
                    <div class="form-group">
                        <label for="{{ form.species.label }}"> {{ form.species.label }} </label>
                        {% render_field form.species placeholder=form.species.help_text class+="form-control" %}
                    </div>
                    <div class="form-group">
                        <label for="{{ form.farmer.label }}"> {{ form.farmer.label }} </label>
                        {% render_field form.farmer placeholder=form.farmer.help_text class+="form-control" %}
                    </div>
                    <div class="form-group">
                        <button type="submit" class="btn btn-success">
                            <span class="glyphicon glyphicon-ok"></span> Save
                        </button>
                        <a href="{% url 'home' %}" class="btn btn-default">Cancel</a>
                    </div>
                </form>

        </div>
    </div>
        <!-- Row End --> 
</div>
<!-- Container End -->



{% endblock %}

So i guess i need a Error field in my Template and maybe some Error Context in my View?