Hang with it, keep an open mind, treat each new installation as a complete learning experience and you should do OK. Start learning not only about plants and fish, but about the entire biological structure of aquatic eco-systems. One day, in the not too distant future, a potential customer will ask you a question to which they will expect you to KNOW the correct answer. Good luck and start reading!
"Everybody is ignorant, only on different subjects." - Will Rogers