Help with Creepy Crawler

Tanks been cycling for a week now,
I just did a water change and found these larvae[?] wiggling around. They give me goosebumps and I found that they make some kind of cocoon? I plucked one out and snapped some shots. Any idea what these are? Are they dangerous to fish and or humans?

Worm Pics:
http://i90.photobucket.com/albums/k269/skillfulabbot/worm_2.jpg
http://i90.photobucket.com/albums/k269/skillfulabbot/worm_1.jpg

Cocoon in water:
http://i90.photobucket.com/albums/k269/skillfulabbot/cocoon2.jpg
http://i90.photobucket.com/albums/k269/skillfulabbot/cocoon1.jpg
 
i strongly doubt they're dangerous to fish and in fact, i'll bet many fish species would joyfully make a meal of them. are these IN the water, IN the gravel - or - above the water line?
 
you've got aquatic larvae of the order Diptera, which contains many well known flies such as: blackflies, mosquitoes, horseflies, midges, and the craneflies to name a few.

during the general life cycle, the Diptera undergo complete metamorphosis with a larval, pupal, and adult stage. the larvae are very different in appearance from the adults. the pupal stage is a period of transformation between these two different forms. the larvae are usually found in the bottom sediments, in vegetation, or sometimes suspended from the water surface. most larvae do not swim and have a variety of adaptations for breathing which accounts for their sometimes strange shapes.

larval development can take as little as one week to as long as one year. when the adults are ready to emerge from the pupal case some will do it very quickly while others must take time for their new adult skin to harden.
 
Maybe you could throw out the cocoons. Im guessing that might help.
 
AquariaCentral.com