I have kept the following Dwarf Angelfish over the several years I have been in this hobby…Coral Beauty, Bicolor, Potters, Flame, Keyhole, and Rusty. The Pygmy angels I have kept include the Cherub, Brazilian flame back, and Whitetail( also known as the Pacific Pygmy angelfish. I kept them all in a 75 gallon tank. Nope definitely not all at the same time! Lol! My favorite of all time was the Bicolor. Awesome fish. There seems to be some confusion between Dwarf angelfish and Pygmy angelfish. Some Dwarf angels can grow to around 5 or 6“ whereas Pygmy angels stay around 3”. So there really is a difference between them even though they all fall under the category of Centropyge. Some get pretty large like the Keyhole( you may find this fish also described as the Tibecin angelfish and supposedly can reach 6” although mine reached around 5” and got really aggressive). I wouldn’t really classify this fish as a Dwarf angel honestly. If you want an angel for your Biocube I would suggest the Whitetail angelfish. This fish in my personal experience would probably work and reaches a mature size of around 3” as mine did. Kept him roughly 5 yrs. then gave him to a friend. They are not the most flashy of angels but their max size would make them a good candidate for your tank based on my experience with them. Hopefully others can chime in with their experience and choices as well and you will find through some research yourself that some of these fish get kinda large. They also require a lot of live rock which might present a problem for you down the road due to the size of your tank. All of the angels I have kept pretty much roamed through and around the live rock in my tank and were never really open water swimmers but they will appreciate as much space as you can give them. As far as nipping at corals, none of mine ever touched my corals but I kept them well fed and I think this was key to my success with them all. Fellow reefer of mine keeps a Cherub angel in his Innovative Marine 40 along with a pair of Clownfish and has said he is a model citizen but is very active and cruises the entire tank but behaves himself. So with all of my babbling stated above if I had a Biocube then my two choices for having a small angel would be either a Cherub or Whitetail. Hope this helps with whichever choice you go with.
I had a a pair cherubs in my 300 gallon with 3 dwarf angels and they cruise the hole tank, in and out of the rock work constantly. They were very active and although they are a smaller fish, I feel it would be happier in a larger tank. Sadly i lost both mine about a yrar ago after several years enjoying them. I have been on the look out for another pair of cherubs.