wow i didnt realise this question was still getting asked. i thought that even the horrible fish shops were not giving this bad advice to people now.
to answer the question, no there is no magical poo eating fish. you get fish that help with certain tasks such as bristlenose plecs assist with keeping algae to a minimum, but even with this little work horse in a tank you still need to wipe every now and again. geos turn over sand so it doesnt go anaerobic etc, but you still need to do it yourself every so often to ensure the whole sand bed gets stirred.
getting a fish just to do "chores" in your tank is a bad way to stock, you should get a fish because you like it not because it can get rid of some algae etc. most of them just create more waste than some of your other fish put together anyway, plecs for example.
to answer the question, no there is no magical poo eating fish. you get fish that help with certain tasks such as bristlenose plecs assist with keeping algae to a minimum, but even with this little work horse in a tank you still need to wipe every now and again. geos turn over sand so it doesnt go anaerobic etc, but you still need to do it yourself every so often to ensure the whole sand bed gets stirred.
getting a fish just to do "chores" in your tank is a bad way to stock, you should get a fish because you like it not because it can get rid of some algae etc. most of them just create more waste than some of your other fish put together anyway, plecs for example.