Medical Mayhem makes good on bad practice, Fish Isle baits players with aquarium novelties, and Band of Heroes hits the target thanks to a Thanksgiving recruitment drive.

A number of Facebook-based gaming applications are showing hefty increases in player numbers this week. The two largest games, FarmVille and Café World have what would seem to be minuscule growth rates of 2.8% and 3.6%, but with 69 million and 31 million active users over the last month, that translates to another couple of million users, a huge amount of individuals.

Fish Isle's introduction just over two weeks ago means that an extra 1 million players means that another it has doubled its user base in the last seven days with a mixture of gameplay tweaks and additional content. While it has some way to go to catch up with FishVille and Happy Aquarium in terms of user numbers, it's looking very healthy indeed, especially as it's IGG Inc's first and only Facebook game.

Medical Mayhem has found success with a twist on the resource management genre popularised by Café World, FarmVille, et al. Throwing the genre's pick-and-choose hallmarks into an impossibly chaotic context, it's clear that creating a perfectly orderly gameworld isn't the point - rather, players should enjoy the ride and make mischief in their friends' hospital projects while the going's good.

Band of Heroes, a World War II themed game, had new players installing it in a steady trickle since its late October release. The WWII era has been a staple in PC and console gaming over the last decade, and here Band of Heroes' not inconsiderable fanbase has rocketed up since last week's Thanksgiving holidays in the USA, rising sharply as the number of monthly active players broke the 1 million mark and now teeter on the brink of topping 2 million.

The Facebook games with the biggest increases in monthly active users over the past week on December 4 at 18:00 GMT were:

1. FishVille (22,915,276 = +4,165,534 / 18.2%)
2. Happy Pets (6,564,277 = +2,348,585 / 35.8%)
3. FarmVille (69,761,553 = +1,950,438 / 2.8%)
4. Fish Isle (2,349,718 = +1,201,014 / 51.1%)
5. Café World (31,222,914 = +1,117,460 / 3.6%)
6. Zoo World (3,808,300 = +1,076,315 / 28.3%)
7. Band of Heroes (1,735,842 = +854,482 / 49.2%)
8. Diva Life (3,050,354 = +761,820 / 25.0%)
9. Medical Mayhem (1,117,965 = +673,478 / 60.2%)
10. Treasure Madness (2,380,497 = +575,950 / 24.2%)

Numbers in brackets relate to total monthly users, the weekly increase in users, and the weekly percentage growth.