In all of my years of keeping fish, almost 45 years, that is one fish I could not master. I was 0 for 3, and finally realized that they were not the fish for me.
Baby whales and the elephant nose use electrical impulses to find their food. They prefer darker tanks, if not unlit tanks. They are a low light feeder, thus the reason for the electrical impulses.
They are a rather peaceful fish. Mine stayed in the bottom 1/3 of the tank for the most part.
They are also a truly soft water fish. I tried to keep them with my Discus
in a tank with a pH of around 6.6-6.8. I truly don't know where I went wrong.
Their tank was fairly well planted, but the low light levels and the plants was not a good mix. They are extremely sensitive to their surroundings. Water quality is of great importance. Filtering should not generate too much current.
They are a live feeder, smaller fish, such as guppies, should not be kept with them. I fed mine small glass shrimp and guppies.
They need to be in a larger tank, say 55 gallons or larger. Mine were in a 90g.
I don't know whether I would even try to keep them now, 20+ years after the fact. Believe me when I say that my setup here is far more advanced than anything that was around when I had them before. They are just a challenging fish to keep.