On Monday, Happy Aquarium with 2.26 million daily active users (DAU) passed both Fish World (#11) and My Fishbowl (#15) to become the #10 application on Facebook as well as stake its claim as the one to beat in the Fish Sim game genre.

Fish World’s server outage last week (causing it to lose some customer data) definitely killed some of Fish World’s forward momentum: daily growth in DAU was only 2.1% from the 22nd to the 28th of September, growing from 2.0 million to 2.21 million DAU. Happy Aquarium, which was on the cusp of passing My Fishbowl last week, saw an impressive 17% daily growth during the same period, adding over 1 million daily active users in just five days (from 1.22 million to 2.26 million DAU).