When I am looking at a fish (to do my required homework), I always consult Scott Michael's Marine Fishes. The Consciencious Marine Aquarist by Bob Fenner is great also. I recommend both, especially if you are interested in FO.
Nick Dankin sucks big time. His web site sucks, his books suck, and his articles suck. Have you seen how he is constantly confusing areobic and anerobic, not very helpfull if your hoping to learn from this guy. You hear me Nick "YOU SUCK!"
I used to work in a LFS and i can tell you that re-educating Dankins followers is the most difficult thing to do, because they read it in a book "So it must be true". Reverse flow under gravel my arse.....