Battery for fishfinder

i have a fishfinder from westmarine and i wanted to know if i could use a 9volt square battery on it, and if i could how long will that last. i have a 12 volt from radio shack but im looking for something smaller

depending on where you are american battery in hayward sells good small ff batteries for 12 bucks thats where I bought mine with a charger for 21 Im not advertising just speaking from personal experience

Check out this article for a great small light battery.

http://www.norcalkayakanglers.com/index.php?option=com_content&task=view&id=29&Itemid=42

While I have only used it a few times so far, I have been using a spare Makita drill battery 14.4 volts.  It is fairly small and is easily rechargable.  So for I have not recharged in 12+ hours of use.

thanks for the tips, but if i went with AA batteries would i need 8 of them to equal the 12 volts that the fishfinder calls 4?

The article calls for 10. Still a lot lighter than the the big motorcycle batteries.