hmmm....well, the resistance of pure water is about 18 MΩ/cm. Deans connectors? I dunno, 1 mm apart as a conservative guess, so with pure water the resistance will be about 1.8E6Ω. Now of course it is silly to assume that the pond is pure water, so lets be very conservative and divide that by 4...so we got 4.5E5Ω for the resistance. with the equation I = V/R where I is current, V is voltage and R is resistance we find that 8V/4.5E5Ω = 1.77E-5A. So about 18 micro amps was being discharged from the battery.
Assuming that the pond water was 4 times more conductive than pure water. If you want to assume more it's an easy format to follow

EDIT: using values from [link=http://lakeaccess.org/russ/conductivity.htm]this website[/link] I found that if you dropped it into the atlantic ocean, the water could support about 170 amps.