Though the top 20 most played games contains what are by now 20 familiar names, the increases and decreases in the amount of players each game is attracting reveals more than first meets the eye.

While much of the most popular Facebook apps retain the same amount of regular users as last week, an additional million Facebook users played FarmVille, the default destination for the Facebook gamer. Its makers Zynga have just added some features that focus on one of the USA's premier sporting events, the Super Bowl, so expect this association to interest users even further and look out for similar implementations across other Zynga games.

FishVille and Texas HoldEm Poker swap places once again in fourth and fifth place, with around 500,000 more players on each. Mafia Wars gains the interest of about 600,000 wannabe dons. Zynga games, who own all all four (plus the second placed Café World) are able to maintain their grip at the top of the chart. The growth of these games means that the pressure is on CrowdStar, the makers of second placed game Happy Aquarium, to secure their place in the top five.

Zoo World is a big gainer as nearly 1.5 million more players appreciate its attractions. Having rid itself of a few early stability and difficulty issues, players can trade zoo animals between themselves in an effort to create the perfect zoo experiences.

The scope of Zoo World's resource management mechanic means it has more in common with farming games than the other pet-themed games which appear to need a shot in the arm. While PetVille remains stable, Pet Society shed 400,000 users, and Happy Pets took a turn for the worse, with around 300,000 users staying away as compared to last week's reading.

The trend for fish games also appears to be waning. While FishVille gained the affections of 700,000 players, Happy Aquarium actually lost 400,000 and Fish World is almost certainly on its way out of the top 20 unless Tall Tree Games can do something to revive interest, losing 600,000 players - nearly 10% of its total player base.

However, Fish World's troubles lower the threshold required to break into the top 20 and could lead to joy for Playdom, the makers of Tiki Farm. Tiki Farm was one of the fastest growing games of the week, adding just short of 600,000 (equalling the amount of players failing to return to the Farm Town game) and currently comes in at 22nd.

Sorority Life, another Playdom game, is in 21st but has been flat in recent weeks. In contrast, Tiki Farm has been receiving increasing interest thanks in part to its implementation of Tiki Farm Achievements and associated rewards that players can work towards.

Most active Facebook games on January 29 at 14:30 GMT
01. FarmVille (75,202,137)
02. Café World (30,318,438)
03. Happy Aquarium (27,770,589)
04. FishVille (25,167,566)
05. Texas HoldEm Poker (24,986,555)
06. Mafia Wars (24,174,812)
07. Pet Society (19,350,560)
08. PetVille (17,970,006)
09. MindJolt Games (16,022,962)
10. Zoo World (15,580,024)
11. YoVille (14,819,959)
12. Restaurant City (14,517,272)
13. Farm Town (13,166,498)
14. Happy Pets (10,774,908)
15. Happy Island (10,190,254)
16. Bejeweled Blitz (9,524,810)
17. Country Life (7,948,844)
18. Roller Coaster Kingdom (7,822,440)
19. Island Paradise (7,329,963)
20. Fish World (6,374,665)
Numbers in brackets relate to total monthly users.
source: appdata.com