Media buying and planning firm Aegis Group’s latest acquisition is a little off the beaten path. It has bought fellow London-based company Clownfish, which helps advise marketers on crafting more eco-friendly, “sustainable” initiatives. The acquisition’s terms weren’t detailed, though Aegis said Clownfish has £500,000 in gross assets. While the purchase would seem to have little to do with digital media, Aegis insists that it does. Clownfish will be folded into Aegis’ Isobar search ad network, as the company says it sees a clear relationship between the online and environmentally sound business practices. Overall, Aegis has been stepping up its buying activities lately. Last month it bought U.S.-based search engine marketer Range Online Media for Isobar, its sixth acquisition this year. Release