Here is my story, take what you will from it
I let my 6 peppered cory cats breed thinking a carnivore species I bought would eat the eggs...they did not eat the eggs.
When the eggs hatched, I thought they would eat the fry, they did not.
I had over 300 fry.
I sold some on aquabid, but I had to buy all the shipping supplies. I was not trying to make a profit, just wanted to get rid of them. They were free, the price I charged was the actual shipping cost. I only got rid of 80 fish that way. It was a pain.
I tried to sell them on craiglist for a dollar a piece, I had no takers. When I listed them for free, I did manage to get rid of some but no many.
Mostly the fry went to a local pet store for store credit, I did not really ask for store credit, I was just thankful he took them.
The local pet store asked me to breed again, he said the demand is for mostly bristle nose plecos and corys. He said live bearers and cichlids are too easy to come by. Most people (the market) buy fish on a whim and buy common stock.
I was not interested in breeding, to me there is a problem with getting rid of the extra fish.
If you breed hard to come by species, you have a smaller market to sell to because the common folk don't know what they are.
Now my son, while in college made his money selling ramshorn snails. He made more money than working at McDonalds. He was successful because there is a high demand for them. Many species of fish need snails for food. Many people ordered a 100 at a time. He sold mostly on ebay and shipping was a lot easier than shipping fish.
You just have to be careful of state regulations of which states will accept them.
That's my 2 cents worth from experience, I hope this helps
