Convicts are real easy but not profitable. African cichlids seem to be reproducing at an alarming rate in all the tanks that I installed/service.
Bad information. Stingrays are not that profitable after including their cost of care, large enclosure to house them, their long gastration period, and low about of offsprings. What marine fish are you referring to which are profitable?Cichlids are easy to raise from fry - and good pairs pump out fry like nothing else - and you get a LOT of fry in a very short period of time. The trick will be to actually build a customer base from the very beginning. Talk to your local pet stores FIRST, and make sure they will take them. Depending on your level of skill; you could also go with something that is very slow to breed, but profitable, such as stingrays, or even some marine fish, or some of the more rare cichlids. People often suggest livebearers, but the profit turnout seems to be very low, since it takes a lot, to get a marketable amount of fry. Also - to state the obvious - we don't even know what you have, to start with, equipment wise. Keep us updated!