White Ribbon Eel is very different from the Blue Ribbon Eel. Despite the similar common names, they are not closely related. White Ribbon Eels can be very hardy. I recall reading an article about the WRE. The author stated that he found it in a live rock holding tank where it had been for a few months before anyone noticed it.
Regardless, I wouldn't put one in a 30g, if that's what you're thinking, Chef.
And bawla, you said you "had" one. What happened, did it go for a stroll?