eagerinsight

I came home from a 7 day vacation and found hundreds of the small white worms or snails on every square inch of my 20 gallon tank. What are these? I immediately scraped the glass and did a major water change. They are not attached to the fish FYI.

john&jen

Most likely Planaria. I had them too. Most likely caused by overfeeding/ generic fish food. Frequent water changes and a good substrate cleaning takes care of it. I will presume you dumped a boatload of food for the vacation. They go away. My fish ate them too.