Lets not even go to the Japanese koi
. They get insane with those. There are fish shows around here, they are fun. I always take way too many pictures. It is all in the breeding. You can get a run of the mill or pure strain guppy for $3 or less around here easy. Yet, there are a number of show quality strains in the local club and at auction a trio can run $20 or more easy.
What you are breeding and quality is key... it needs to have demand and you need a way ideally to sell it straight to someone else, don't deal with store credit if you don't have to. Shops around here give you 1/3 of retail price when you sell fish, which is fine IF you are trying to get rid of them. If your goal is to actually sell them then its the wrong approach... This is a hobby for me nothing more, but I can easily sell $100 or more in excess plants online in a summer. Auctions are hit and miss. I buy and sell so break even in costs usually. I just got $71 in the mail from the last auction, so I made like a whole $5 over what I spent there
. Thats not the point really though, new stuff is WAY cooler then the stuff I got rid of. BTW its way easier to sell plants then fish IMO...