Plant Identification

I need help identifying this plant, I received a small piece from a large plant that my aunt had in Waco Tx. Upon my return home to Northern Va, I put it in a small fishbowl of water and 3 or so years later it's outgrown it's bowl and I need to transplant it. However I can't find any images that look like this plant to find out the info I need to do a transplant with out killing it.

Thanks,

 

Epiphyllum, maybe.

 

Ditto to Epiphyllum.

 

Shouldn't be impossible to move it to a bigger pot. Stringy growth is from inadequate light.