Guggenheim Solar Energy ETF ( TAN) -2.4% The solar energy industry is taking a hit, retreating back to levels seen prior to the fund's 2011 run up. Though gut-wrenching, TAN's back-and-forth performance in 2011 is not surprising given the volatile nature of the alternative energy industry. Investors willing to try their luck with this fund will want to keep exposure small. Global X/InterBolsa FTSE Colombia 20 ETF ( GXG) -1.9% The Colombian markets are taking a hit today as oil prices get knocked. GXG's index is heavily weighted towards the energy industry with top holding Ecopetrol ( EC) representing over 16% of the fund's total portfolio. In total, oil and gas companies represent more than a third of GXG's index. All prices as of 2:15 PM EST Written by Don Dion in Williamstown, Mass.