here's a good DIY fish trap that you can make with a soda bottle:
cut a soda bottle right above the label, where the straight sides become curved sides. you'll have what looks like a funnel. take the label off and clean the bottle out real good. insert the top of the bottle (without cap on it, of course) into the bottom part, so the threaded top part is close to the bottom of the lower half. put some of your clown gobies favorite food in the trap. it will be a lot easier for the fish to swim in, than swim out. once the fish is in the trap, just remove the trap with the fish in it!. much easier than tearing apart your aquascape!