this is Heiko Bleher and I just saw the photos of what you all call baby whales. Well it id a mormyrid and this, and most other mormyrids or as in europe called elephant fishes, NEED fine substrate.
Where they live in Africa (and I collected many mormyrids all over, as they have and live always were is soft underground, like fine sand, mud, as they need to dig into this soft substarte and take out the accumulated microorganism.
You will never be able to keep them successfully unless you give them such a substrate and naturally feed them well (they love blood worms, daphnia, tubifex, and other live or frozen foods).
The tank decoration yo have is not adequate.
Please look also for my biotope aquariums (Bleher's Biotopes) on my website:www.aquapress-bleher.com
and look for Malebo Pool Aquarium. You see the substrate and also the habitat of such mormyrids.