If you are coming to the Bay Islands for
big fish, you will be looking for the wrong thing.
Pretty much so you can save money and go to the Bahamas if you want to see Groupers, Baracudas and the like. Yes, you are more likely to see Whale Sharks in the Bay Islands, but that is best in a few months at select lunar phases. To go expecting Whale Sharks is folly, to go and stumble into them- that's a bonus.
You can go anywhere in the Caribbean to see Lobsters and Crabs, but as you mention "Dee's" photos, you must understand that the South shore of Roatan is what sets the Bay Islands apart from the rest of the Caribbean.
It's the small stuff.
Dee is set up for macro photo. If a big critter swam by, not only would she not be set up to photograph it, but Dee has seen a Turtle, a Ray, a Shark (or two). Trust me, after the 10th Shark- enough already. Got my turtle... check.
Now... can we go looking for Pipefish and Arrow Blennies... something really cool?
I can't tell you how many dives that I have done, right next to Dee, when one or the other of us saw a 3' Baracuda and didn't even bother to get the other's attention. Okay, another Baracuda. In your first 30 logged relaxed warm water dives, if you don't see three baracuda- you just weren't looking! The cool stuff is tiny- half dollar sized down to pin-point tiny.
The South side of Roatan is a nursery that is visible to
advanced divers with excellent buoyancy and observational skills. Many better divers carry magnifying glasses and move very little during any dive.
"Advanced" diving can mean many things, but I always point out that it represents skill sets that must be understood and honed to be attained. This kind of advanced diving... no- it isn't life threatening if you don't master it, but thorough mastery of buoyancy and observation can make the difference between a standard caribbean dive trip versus the
wonderment of the Bay Islands.
More microscopic wonders? See
http://www.docksidedivecenter.com/WeeklyLog.html (also look at "previous weeks")
When the time comes, you'll see the big stuff swimming by- in the mean time, go find yourself an Anemone Crab or SeaHorse.