They dont need as big a tank as you would think... They dont get bigger then 2 feet in the home aquarium very often and they sorta just lay there like a log so there is no point in wasting a huge tank for him when he will eliminate anythig in there... This is one of the few fish that can actually outmatch a Piranha. You can find some intresting articles on the net... about their extra sensory perception.
From what I have read the 350 volts is from full grown adults. Small one's tingle and the bigger they get the bigger the shock, just like electric eels. Cool fish, I have one that is over 8". And he's fat. Likes to swim around when the lights are out.
I've never heard of an e cat delivering 650 volts. I have only heard of eels delivering that much. I have read countless articles on e-cats and they all pretty much say the same....1 meter specimens produce 300 to 350 volts. Where have you been getting this info? Electric eels get somewhere around 7 foot max and put out about 700 volts. Voltage increases with size.
I'm not trying to start a fight I would just like to see where you got this info?