Big animal

I was fishing this small body of water it's usually only full of panfish and crappie. I've catched some 5lb bass and recently saw some small gar. anyways I saw something massive in the water it was at almost 2 ft wide and super long it passed by and I only saw sections of it's body as it moved to the surface and dove down. it was light grey i have no clue what it was but it was huge any ideas? am I silly for thinking it's an anaconda someone dumped