How did you get into this line of work?

A combination of hard work and luck. (Anyone who says it's all about hard work is lying.) For over 20 years I funded my own low-budget expeditions, paying for them by selling occasional press articles and doing other odd jobs, and by living a very frugal life in between: no permanent home, no car for 15 years, no holidays in the normal sense. During this time I became an expert in a subject that few other people were interested in - until suddenly we were in a situation where freshwater fish were the only remaining group of creatures that hadn't received the full natural history TV treatment (because you can't see or film very much in muddy water). And the rest, as they say, is history....