Im sorry but the retailer do not (in general) have high mark ups.
What I suggest you do is have a rough look at what they will sell in a day.
If they are lucky they will have a 100% margin which would produce a 50% gross profit.
From that profit they need to pay rent (probably $500 minimum) power, wages, advertising, stock failure, ACC, public liability, insurance, holliday pay, sick pay and maintence. With whats left, they have to keep them selves fed and clothed. Now for the investment they have made and the commitment, I personally dont belive they are making enough.
As an importer, you will need to bring in huge amounts of fish so that you can supply everyones needs (mine happen to be Killifish) so I will need you to bring in at least 15 specie. When (note when) you loose a certian amount MAF will come and take the rest away and distroy them so they can find out whats wrong with them only to find that stres has killed them but not to mater as you have just had to pay for your fish to be killed and disected.
Still, dosnt matter as you can make it up on the next shipment only to find that the fish you were getting in for me (killifish) are no longer on the suppliers list and no I dont want what is already here thanks
Good on you if you do it but please dont knock the retailers that are here that you will need to supply when you get your fish imported.
(by the way, Im a glass merchant and get sick and tired of people telling me my margins are too large when they simply have no idea on business at all)
I honestly dont mean to give you a hard time and am sorry if you see it this way