cowfish cautions

[Aquamarina]

I am sorry there has been some strife, apparently over a concern about hurting my feelings. I am aware that I am a raw beginner, literally thrown in at the deep end of the tank, and constructive criticism and advice are what I need! So please don't worry--I will stick my head in the aquarium if I feel demoralized! I am guessing what "LFS" is, but would like to know for sure...

To answer a couple of queries:
I think the butterfly is a Heniochus, but not quite like the picture.

The tangs are about 5" nose to tail. Not quite sure how I would remove one as they slide into the narrowest crannies. The wrasse and the trigger are similar sizes at about 6-7".

What is "nori"? I have been feeding frozen food of several different sorts, eg. plankton, mysis shrimp, emerald entree, marine cuisine, salt water multi-pak, bloodworms. I usually feed one cube of each, once daily. A prof. fish guy who came to help me in the quarantine tank emergency told me the fish look healthy, the tangs are a great colour, and the water quality is excellent.

Filtration: the bio ball tower is 18x8x39" and drips into another tank full of bio balls 10x8x20" on its way to the recirc. tank.
Protein skimmer is a Remora AquaC, EV 240 (I found the instructions on the internet and am going by the picture and the dimensions quoted) installed in 2000.

I do a 10% change once a month, and even just before the change, the water tests out ok (pH, ammonia, nitrite, nitrate).

Thanks again for your interest!