parasites in 5 gal tank?
i recently bought an electric blue crayfish and was forced to put it in a new tank. its in a 5 gal glass tank right now (by itself) until it outgrows it. last night i noticed that there were small white spots flicking around the tank which i, at first, thought were baby crayfish (altho far too small). some of these tiny white bugs looked like they had they crayfish type tail; an oval body and a heart shaped "tail", while others looked like what can best be described as what sperm looks like under a microscope (white body, thin tail). i also noticed some very minute worms on the walls of the aquarium. they're about as thick as a strand of hair, only about 1mm or so long, and pink/red in color.
my main concern is if these are parasites or not and if they are, can they be harmfull to crayfish. i bought some elodea which i put in the tank brefly (2 days), but had to take out cause they looked like they were dying. im wondering if this may not have been the mode of introduction of these pests into the tank.
my other main concern is that i have a crayfish in the tank, and that most medicines attack invertebrates and would kill the crayfish as well. i've heard of using salt water (im assuming not table salt) to avoid any such problems, but i have ZERO experience with that, and would be afraid of doing damage.
i am planning to do a water change tomorrow- probably about 50-70% (altho i might do 100% change).
any advice would be greatly apreciated. thanks!