Syed, they preffer food rather than fish excreta,
my readings on these based on many experiments.
1. They love a good powdered mix of food (grains, pulses, fish food etc)
2. If kept on a protein diet they tend to crash and are not very stable.
3. same with Fats or any excess element.
4. They like clean water and do not like very high or low temperatures.
5. I have tried feeding them dead shrimps or fish but they don't seem too interested.
Forum for discuss on fish/Invertebrates food.