Why on earth would someone not feed the fish
Feeding takes me an hour every morning to do the main feed (doing a round of trop flakes, goldfish pellets, marine pellets, algae wafers, novo tabs, spirulina flakes, catfish pellets, pond sticks, bloodworm, artemia, krill/mysis, cichlid sticks, cockle, mussel, prawn and then live artemia naupilii for marines).
Then throughout day different fish get extra feeds, a second flake/pellet feed, catfish sinking food and some frozen foods.
Feeding is one of the most important things for happy healthy fish

makes me sad to think people dont bother or dont feed much or variety. I even buy courgette or cucumber for plecs sometimes!
If the fish arent fed right they will be unhappy, lacking in colour, huddled, thin... whats the point? If you want to sell fish then you need them to look good, any retailer that cant work this out shouldnt have the job. Its not just cruel its just plain stupid and lacking in any kind of business sense.