Hi @Max7,
Thanks for the updates.
Did you see the feature-table summarize action in this section of the tutorial? This will give a summary results of your feature-table following DADA2. In the same tutorial, under the DADA2 section:
qiime metadata tabulate \
--m-input-file stats-dada2.qza \
--o-visualization stats-dada2.qzv
This will also give you a summary of the DADA2 stats results.
Yes please, this will be quite useful for a quick check, but keep in mind that GG is for 16S only, and it looks like you are dealing with non-bacteria, fish? So GG won't work here, you'll want to use a different database that has your marker gene. For example if its 18S, Silva will have one that should work.
Your reference database looks rather funky and messy to me, but I can't tell if that's just the formatting when you pasted the data over or that is in fact what it looks like. If you want you can share your database with us and we can have better look that way, or better yet, have you seen this tutorial on making your own custom reference database with RESCRIPt? This might be the cleanest way for you to build one. You can also search through the forum regarding custom reference database and see some of the common issues with those, maybe this, as a starting point..
Hope this helps.