Custom Taxonomy Pagination Not Functioning - php

Question

I have set up CPT with a custom taxonomy, yet I cannot get pagination working. First page renders fine but when I click through to "/page/2/", I get a 404 error.
I have a CPT named "species_guide" and a custom taxonomy named "species".
I attempted the solution outlined here: https://wpza.net/how-to-paginate-a-custom-post-type-in-wordpress/ and https://wpza.net/how-to-a-paginate-custom-taxonomy-archive-in-wordpress/ but to no avail.
Below is my code, any input would be appreciated:
in taxonomy-species.php I have the following:
<?php
$paged = ( get_query_var( 'paged' ) ) ? get_query_var( 'paged' ) : 1;
$term_slug = get_query_var('species');
$args = array(
'post_type' => 'species_guide',
'tax_query' => array(
array(
'taxonomy' => 'species',//custom taxonomy name
'field' => 'slug',
'terms' => $term_slug
)
),
'posts_per_page' => 10,
'paged' => $paged
);
$loop = new WP_Query( $args );
while ( $loop->have_posts() ) : $loop->the_post();
get_template_part( 'templates/post-archive' );
endwhile;
?>
<div class="pagination">
<?php
$big = 999999999;
echo paginate_links( array(
'base' => str_replace( $big, '%#%', get_pagenum_link( $big ) ),
'format' => '?paged=%#%',
'current' => max( 1, get_query_var('paged') ),
'total' => $loop->max_num_pages,
'prev_text' => '«',
'next_text' => '»'
) );
wp_reset_postdata();
?>
and then in functions.php I have the following
function custom_tax_query_change( $query ) {
if ( ! is_admin() && $query->is_tax( 'species' ) ) {
$query->set( 'posts_per_page', 10 );
}
}
add_action( 'pre_get_posts', 'custom_tax_query_change' );
Should I be using the different species slugs in the is_tax() function? Not sure why I can't get this working

Answer 1

Your taxonomy template name should be taxonomy-species.php to match the taxonomy name, see WordPress documentation
You don't need to create a new instance of WP_Query() for the loop, simply copy existing taxonomy.php or archive.php file and name the file as described above. Make HTML/PHP changes as needed.
Here is the updated snippet for pagination:
<?php
// for total pages in the loop.
global $wp_query;
$big = 999999999;
echo paginate_links(
array(
'base' => str_replace( $big, '%#%', esc_url( get_pagenum_link( $big ) ) ),
'format' => '?paged=%#%',
'current' => max( 1, get_query_var('paged') ),
'total' => $wp_query->max_num_pages,
'prev_text' => '«',
'next_text' => '»'
)
);
?>