The more you dive the more you will learn. Buy some coral and fish identification books. Paul Humanns are very good.
https://www.amazon.ca/Reef-Set-Flori.../dp/1878348337
If you want to avoid the tourist oriented dive ops, use the smaller shops that are able to cater to personal preferences. Smaller dive groups allow for more personal attention and dive masters that can take their time and point out interesting stuff.
Or you can go the DIY route. Consider visiting Bonaire where shore diving rules and you have the freedom to dive where ever and whenever you want. We are returning for our third trip this winter. Your dive boat is your pickup truck and you are your own divemaster. Can't wait to get back!
Forgot to mention that there are PADI specialties in fish identification, but the cynic in me says it is just another way for PADI to extract more cash from your wallet, and it is something you can easily learn yourself.