100g, but is really 95g, is same foot print as a 75 but a tall, I have had a few, the benie of it is more water volume and more up and down for the fish. all my Oscars used every inch of up and down, I pesonaly do not like 75g because they shallow. I prefer tall tanks, 95g tall. 145.tall. 180 tall. is the way to go for me, like that wall of water and fish got more than back and forth. esp a bigger fish like an oscar.