How do you produce biodiesel from fish?

Question

I want to produce biodiesel from fish excrement.

Answer 1

If you can create a process to feed aerobic or anaerobic bacteria or algae on the excrement, you could eventually convert that bacteria or algae into a bio-fuel.  The process does not sound promising or economically viable though.  The energy potential of fish excrement is much lower than of other sources more easily accessible.

Answer 2

Bio-diesel is made from fats, not excrement.  You can make it from fish oil.