It depends on how big is your tank, algae eaters come in all sizes. Personally I don't think is a really good idea to add fish or other animals for the sole purpose of eating algae, as you have to consider compatibility and avoiding overstocking.
I would recommend:
1. Do not add any fertilizer to your fishtank unless you keep a species of plant that specifically needs so. Plants usually just use traces of elements in the water, and the excess of them cause algae blooms. You might also consider installing a CO2 system if your tank is heavily planted.
2. Reduce the time or the intensity of light, if its too strong.
3. Introduce a fast-growth plant that can suck out all nutrient from water quickly, like Asian Ambulia or change water and introduce a less demanding plant, such as anubias.
4. Just scrub with a brush or a sponge (if you're not too lazy)