Fermentation waste biomass of filamentous fungi is generally disposed off either by land-filling or incineration. Its employment as a biosorbent attains ecological significance in removing toxicants, especially heavy metals from waste water. The biomass waste of Aspergillus terreus showed high copper sorption capacity to the tune of 224 mg/g dry wt. The fungal mycelium proved to be a good bio-indicator of copper as even at 1 ppm Cu2+, it attained blue colour which became darker with increase in the level of Cu2+ in the medium. Besides this, even in a multi-ion medium containing Zn2+ and Co2+, the copper biosorption was visually indicated, thereby showing its preference for the metal.