Big Fish Games is launching a game for the Amazon Kindle electronic book reader today as part of a diversification into new markets.

The Kindle has primarily been an eBook reader to date, so this move shows that just about any electronic gadget — even those that weren’t meant to host games — can become game-playing devices over time. It could also be a harbinger of more things to come, since Amazon is reportedly working on a tablet computer for launch this fall as it tries to cope with the fast growth of Apple’s iPad.

Patrick Wylie, vice president of Big Fish Game Studios, said the Kindle game — Hidden Expedition: Amazon — is an attempt to satisfy existing game fans and find new ones as well.

Hidden Expedition is a hidden object game, where the goal is to search through scenes to find items. The graphical detail on the Kindle — even though it is in black and white — looks pretty cool thanks to what Big Fish Games was able to do with the latest E-Ink Pearl technology behind the Kindle’s low-power screen. Each scene has been remastered for the E-Ink display.

The game has 19 levels and is available in the Kindle Store for $4.99. In the game, you go on an adventure on the Amazon River, searching for a missing professor.

Big Fish is also diversifying into other areas. The company grew up primarily as a maker of casual games for women on its own web portal. But it has been expanding heavily into iPad games for the past year and today is also launching Mahjong Towers Touch HD for iPad. The company also released a new Mystery Case Files game for the Nintendo Wii.

Seattle-based Big Fish Games was founded nine years ago by Paul Thelen with a $10,000 investment and a Mahjong game. Big Fish now has more than 500 game development partners and games available in 10 languages.