Some sites list them not reef safe because they will obviously eat shrimp,,but thats it..They won't eat your CUC or nip corals ...
As far as hiding spaces ,,,neither of mine EVER hide..They are always out on top of a rocked or on the side of it,sitting perfectly still,looking and scanning for the next meal
I would just make the scape to your liking and the angler will be fine with it..
This is exactly what I plan to do. Looking into several aquascapes, one of my favorites was done by André Silvestre. He also wrote this article about aquascape techniques:
Aquascaping your Reef Tank
Certainly the (5) main points that he brings up are what I am trying to attain in my own tank:
- Good water flow around and through the whole rockwork
- Fish shelters
-
Fish swimming area
- Coral area
- Natural and aesthetic feeling of the rockwork
I realize that the "swimming area" isn't of huge concern for an angler as they are more cryptic fish and mainly sit and wait, but you get the idea nonetheless.
With my current reef tank, it looks "good", but it doesn't look like a reef. It looks like a bunch of nice looking corals put together on a big rock pile with a few fish swimming around it. I'm happy with it, but it is far from natural, which is where I want to go with this build. I want to try to duplicate a natual angler habitat for the fish's sake, and my own.
Researching on habitat has led me to find that these specific Anglers are typically from shallower waters with foliage, algae, debris, and lots of sponges around to sit on, near, lean on, etc. I want my angler to be able to show off that awesome camoflage.
Unfortunately, I've read several sources, two of which are included below about the care of sponges in the home aquarium, which seems to be about as hard as keeping NPS corals.
http://www.advancedaquarist.com/2004/4/inverts
http://www.advancedaquarist.com/2011/6/inverts2
Aside from that, I am still going to try to find "similar" substitues that appear to be from a Natural habitat.
This will certainly be a challenge, but I think it will be rewarding, and something that you don't necessarily see or think about when inquiring about a "reef" tank.