I wouldn't say there would be much profit after you've covered what you've spent/still spending.
I think we have all wanted to be breeders at some stage and whilst it does look a promising ammount of cash you'll get in return I cannot see it myself. Extra tanks means more money going out, more fish means more fish food. If your wanting to grow them out yourself you'll also need bigger tanks and although you will get more money for them at a bigger size you will also spend more money getting them to that size.
For the likes or livebearers I really don't know how they make a profit. A fish that often breeds but its fry sell to the end user for around £2. Whilst all the money, time and effort, packaging, transportation and everything else that all costs money I believe would outweigh that £2 by far.
Sorry, I went off on one.
In answer to your question, you'll maybe make money out of it, I doubt I would though.