Parasites, snails, or what?

Question
QUESTION: Hi Dave, my daughter has an aquarium and has developed a problem with it.  We are unsure if the white bug like things are snails, or parasites.  We took a water sample to Petsmart but they could not tell us what they are.  We tried LifeGuard to clear up the problem but 2 weeks later it returned.  She only has a large snail and plecostumus in the tank now.  She used to have Glo Fish but they all died as well as the Zebra fish we bought.  The Pleco is fairly good sized now.

ANSWER: Hi Shelly:  If they are small white worms on the glass then they are called planaria and are harmless... let me know... dave

---------- FOLLOW-UP ----------

QUESTION: Dave, the tiny white bugs are everywhere in the tank.  They are hanging out on the wood for the pleco and the plastic plants she bought.  They are not out of the water but in the water.  We see a concentrated amount on the plastic tubing that covers the heater at the top but still in the water.  They are so small, no pictures are possible. My daughter says they look the head of a pin when she looked at them thru my magnifying glasses she states they look as if they have little worm like legs coming off of them.  I can't see that well, call it aging eyes.

ANSWER: Hi Shelly:  I would treat them with aquarium salt for now... if it looks like they begin to bother the fish then I would treat them with a copper based medication.  However, for the meantime I would just let them be.  They are probably something benign.  dave

---------- FOLLOW-UP ----------

QUESTION: These creatures are on the fish now.  When you are talking aquarium salt will it hurt these fish they are freshwater?
Should the fish be removed from the tank while we are treating the water?

Answer
Hi Shelly:  if they are on the fish then I would treat the tank with a copper based medication... or flukes tabs... treat all of the fish so do not remove them from the tank.... aquarium salt he a great preventative to other diseases... it will not harm freshwater fish unless you put too much in.  dave