It is an open top. I only have one royal gramma in there. Here is the tank stats.
Hardwear
20g tank
Bakpak skimmer
Coralife 130watt PC lighting
2 - 301 power heads
Calcium reactor (Ocean Aquastics style)
5lb bottle
Sumping the tank in a couple months
Live stock
Branching Hammer coral, GreenOpen Brain, Red Open Brain, Grape coral, Leather coral, GSP's,Trumpet coral,
Moon coral(Brain), Montipora Digita, BTA
Fish
Royal Gramma, Tank Breed Clown, Six Line Wrasse.
This pic was taken a couple weeks ago. I have since done some renovating. I will post more when I get my tank cleaned and get a couple good shots.