UFOs in tank water

Question
Hello Chris,
~Our tank has been set up for about 2+ months, 20 gallon and the fish were transfered to this bigger tank for more room.
~1 - 6" plecko, 1 - 3" catfish type, 1 - 3" sucker type, 2 - 2" yellow shell snails
~gravel and 1 air stone filtration
~ph & ammonia are normal, nitrites are ?
Question: There are 1/8" long, hair-thin, squirmy swimming worms and I have never had these before. The snails are the only news items in the tank besides some decorations, gravel, etc. What the heck are they and what do we do next? Thanks for your time in this matter because I have spend a good part of an hour (on internet) trying to find something on these things and to no avail. Odile

Answer
Hi Odile;

These are a type of "Planaria" and are harmless to your fish. They are feeding off excess fish waste from overfeeding. Most of us do from time to time. We just have to be prepared to clean up after ourselves when we do.

The only way to get rid of them is by starving them out. Vacuum the gravel while making partial water changes of 25%. Do this cleaning twice a week until the planaria and wastes in the gravel that they are feeding on are clearing out. Cut back on how much food you feed the fish too. Eventually the planaria population will decrease and the fish will be healthier and happier too. Without these little living "warning signals" your tank was on it's way to having a very serious problem. Usually, hobbyists don't know there is a problem until fish start looking sick.

After the crisis is over and the planaria seem to have faded away, do a gravel vacuuming with 25% water change every week to two weeks. This is just regular maintenance that you should do for the life of your tank.

Followups welcome.

At Your Service;
Chris Robbins