something in my tank

Question
hi i have a 55 freshwater tank and i have had it for a yr now and all has been great  , this isnt my first time  , so i'm not new to it , but i am new to this , i have found the other day a patch of little white looking worms just in one area of the tank on top of the glass right above the water line and one or 2 on the glass in the water , and i dont know what it is , and i havent seen them in a few days now and just saw one the other day, what is it ,? will it hurt my fish , what can i get make it leave , i just did a water change last week i do them every 3 weeks shold istart doing it every other week ? i have guppys platys mollies 3 fighing fish a white rainbow shark tetras a few clams i had crabs but they only lasted 6 months... and i have 2 fish that i dont know what they are they are clear with color lines on them and i have sniles like you wouldnt beliveee that came from no where i thought i trashed them all but they are back lol , i hate snils lol . oh and i have well had 2 cory but one died a few months ago so sunday i bough 4 white cory but only put 2 in the 55 gallon and 2 in my 20 gallon long ,  i want to make sure that the worm like things will not kill my fish and if its coming from them , i only feed them once in the am and once at night and i put the light on at 4 -12 and 2 times a week i dont put it on at all , and sometimes i dont put it on till 8 , so what should i do

Answer
Hi,

The worms are Planaria. These worms are caused by bad water quality, and/or excess feeding. fortunately, they won't harm your fish, although they look repulsive. In your case, the worms are in your aquarium because of poor water quality. How do I know that you have poor water quality? Because you only change the water once every three weeks. You should change the water EVERY WEEK, to prevent any toxic compounds and waste from building up.

There isn't any chemicals designed exclusively for the removal of Planaria, so I would do it the natural way. (the safest way for your fish.) Change 20% of the water every two days (Yes, every TWO days!), and perform a gravel vacuuming with each water change, to remove trapped waste from the gravel. After about two weeks, if you don't over feed, and perform the water changes, the Planaria should be gone.

After the worms go away, then switch to a normal routine of a 20% water change every week. Performing water changes every week is important to maintain water quality. after all, do you want more worms?

P.S. Just a quick tip, removing snails is easy. Just before you go to bed, place some lettuce in the bottom of the tank. the next morning, it will be covered with snails. Dispose!

Good Luck, and best wishes!