dude, forget breeding fishes, and sale it for nothing, also it will take months to get babies selling size, if u wanna make some extra money do what i do:
make an ebay account and paypal, maybe u already have , and start buying GSM cell phones, and sale it back on e bay or craigslist, i have doing this for about 3 year now, i just spent 1 hour almost every day after my workon my free time, , i am buying and selling phones on ebay, like last month i put 2500$ to my bank account, atlees i made 1500$ from that sales, only thing u haven to lear lot about gsm phones and some time buy whole sales and fix some ofthem or get parts from them, i am sure u can find lot of good deals buying gsm phones, beacuse outthere lot of peole doesnt know how much worth the phones and they sale it half prices, what u doo buy it and sale it for regular or some time for more much money,like last month i bought whole sale 13 phones for 350$ and i already sold 3 of them for more than 350$ and i still have 10 more phones for sale and i am sure i can sale them more than 800$, like another last week i got phone 180$ and i sold it 3 day later for 320$ u see, u can makes some money without do anything, just spent hour on the pc. i am saying u breedign fishes or having fish tanks for hobby only, u can not make money with breeding fishes, maybe some, but not like selling phones, also u will be using the best phones everytime, like me i have the best phone on the market and i got it for realy cheap price, , anyway this is just my opinion do it or not,
good luck to you