If I've got my eye on two different types of Angels for my 55g, would they get along with eachother or are Angels better left getting one? I'm looking into a Black Lace/Veil and either a Marble or Koi. Should I make sure to sex them or what? Other inhabitants will include a few Rainbowfish, possibly 2 Silver Dollars, 2 common plecos (4- 5" and 3-4") and possibly 3 Network Corys. Not looking to breed, just to make them as comfortable and happy as possible.