Note: please do not get a fish just to clean up algae. If you want it because it is "cool" than go for it, but keep in mind that the majority of the time algae can be taken care of without the use of fish. What is your lighting? How long are they on? How often do you feed? What is your maintenance routine like? Usually it boils down to too much light and/or too many nutrients due to overfeeding or a crowded tank. Adding fish only increases the nutrient side of the equation as all fish add bioload to the tank. Also, the type of algae matters as well...do you have an idea which type you are dealing with? Not all fish will munch on the same algae.
Sorry for the rant, but many people get sucked in to thinking that adding a pleco or a similar species will magically solve their algae problem. If you really want one, look into bristlenoses (also called BN plecos) from the genus Ancistrus. There are other ones available, although less common than the BNs, such as bulldogs/rubberlips, clowns etc.