Really tough to stay in business and offer truly fully QT'd and vetted fish with a warranty. I do it, but only offer the service to my private clients who have ongoing tank maintenance accounts. It saves me money in the long run by having as near zero fish losses in client tanks as possible which leads to less nonscheduled service requests and a very robust referral network from satisfied customers who see the difference. Now, do I make money on the fish sales themselves? No. I pretty much break even when factoring in how much loss I deal with and labor is put into each fish. I charge a higher than standard retail price, but its barely enough to cover my associated fish QT overhead.