It was an interesting start. I started with a small 10 gallon tank with some livebearers....mollies and swordtails, in fact. Once I had too my fry to deal with, I posted them for sale on Craigslist.
Got a few e-mails and this guy with a 60 gallon tank wanted them and was only about 20 minutes away and could pick up...called him and we arranged a time for him to drop by. Then before he was supposed to come over, he called and asked me a ton of questions about his setup, his lighting, etc, etc, substrate...and I talked to him for close to an hour before he invited me over to his place to look at his tank.
Needless to say, it was FILTHY. Algae had overgrown the tank, the driftwood had chaeto growing out from it, the "clown puke" substrate was covered with detritus...not a good thing.
I offered to show him how to clean it with a gravel vac and what not...and he offered me to clean it. $150 in fact, to clean it. To me, it looked like a two hour job, so I took it. I got back in my car, got my Python, gravel vac, and some other equipment and went back to his place. It took me freaking 4 hours to clean his darn tank...it was really bad. Long story short, he felt bad and ended up paying me $300 that day and I've been maintaining his aquarium every since.
Through his referrals, I've landed a few more "clients" and many of my weekends are busy with water changes and pruning, but it's decent chump change.
And as for the coral thing...I just got tired of paying out my butt for corals. So now I'll grow them and sell and/or trade for other ones.