[ichthyogeek]

Mormyrids in general:
They're unique in that they produce an electric field that they use to sense other things in their environment.
They are carnivores.
They normally do not do well in groups in small tanks (<50 US Gallons), but one may be held in a 50 gallon tank.
Sources: Various magazines and internet articles

Try wetwebmedia or seriouslyfish to see if they have any additional information that I've forgotten.

 

[ichthyogeek]

Iamiskool, I was talking about the more commonly kept mormyrids, specifically Gnathonemus petersii, or the common elephantnose fish which grows up to 9".

 

[ichthyogeek]

I kept them once in a 2.5 gallon tank and heavy aeration. You really have to rinse them very very well, or else you'll have a giant smelly bacterial outbreak in the culture tank. As in, hook the bag up to the waste water on the RO/DI unit, and let it flush the worms until you have about 10 gallons of RO/DI water. The worms don't have to be refrigerated, but refrigeration does slow their metabolism so that they don't consume oxygen and die from the low oxygen conditions. I added a catappa leaf, and that seemed to increase their lifespan while I used them all up, probably because it was a good food source. If the worms escape in the aquarium, don't worry. They'll live until a fish finds them.
Conclusion: Don't refrigerate if you don't want to, but if not refrigerated, provide lots of aeration. Rinse very very well. Add some sort of food source to keep them going.