Someone at this pet store told me that a golden algee eater need a heater is that true?

I would say so, yes.... I find them mostly in tropicals tanks, and the one I have is also with my tropicals. I don't have them in my goldie's tanks anymore - he was aggressive towards them and hanging onto their scales. Thats a big draw back - as neat as they look otherwise, I would stay away from them if you are planning on putting them into a goldfish tank....

i think so too. i also have one in with my tropicals. i keep the water between 78 and 80. but mine never bothered my bubble eye or black moor while i had them in there. (theyre in their own tank now). so maybe it all depends on the fishie.

I think that they older that they get,the more you start to see the aggression.When mine were small,I never had any problems with algae eater's but as they grew to five/6 inches I really did see them start to harass the bigger fish.

mine was an evil little bugger at just over 1inch..