Yeah it's an old thread but maybe everybody scooping up the supposed FW eels should start reading threads like this before they buy and then whine and cry when the eel dies.
I was going to get a Gymnothorax Polyuranodon but now that I seen another example of the big fail in FW, I guess I will have to pass. No wonder you don't see to any progression threads on these eels...It's plain and simple they don't survive in freshwater.
Really? Wes told me that the group he imported for Li is still doing well several years later in pure freshwater.
There's a giant difference between Polyuranadon and Slathe or whatever the giant slender Morays are. Mainly one can definetly live in FW and one might be able to with special care.