tiny white worms on glass/planaria?

Question
Hello, here is the details of my tank:
1. No fish, only 4 mystery snails about 1-2 inches in size
2. Tank is 16 gallon
3. Snails are very healthy and growing like crazy
4. It is a planted tank (with Flourite Dark as a susbtrate) which includes Anubias, cryps, hairgrass, wisteria, and a moss ball.

Here is the problem, I know the tiny white worms can be typical in tanks but considering I have no fish I am wondering if I should get some fish to eat them or if they will harm my snails. Will the tiny white worms on the glass harm my snails? Should I get a specific type of fish to eat the worms? I have fed my snails algae crisps about 2 times a week but do not put any fish food in the tank yet because I have no fish. I am wanted to get the planted tank established before I add fish. I imagine that the worms came from the plants I got from the store, is this the likely origin of the worms? I say this because there is no extra food on the gravel and the tank is kept clean, as soon as I put the algae crisps in the tank the snails flock to it and eat it till its gone (I also give them lettuce to snack on with a veggie clip). Should I do anything for these worms or just let them starve? My main concern is the snails, I have had them for a while and they do a wonderful job cleaning the tank so I want to make sure the worms will not harm the snails. I was going to get a few oto catfish but I wanted to make sure I should not address the worm issue before I get any actual fish. Will oto catfish eat the worms or will the worms harm the catfish? I have heard loaches do a great job of eating the worms or cory catfish, is this true? Should I get some of those to quickly remove the worms. My goal is to eventually add small angelfish (I will be upgrading my tank so I want to start with small fish for now who get bigger) and some oto catfish or cory catfish. Should I hold off on stocking until the worms are gone? Finally, will the angelfish eat the worms? I have tested my water and here are the results: nitrite = 0, nitrate = 20, hardness = 75 (soft), alkalinity = 80 (moderate), pH = 7.2...Thanks for any help.

Answer
Rachel,
Yes, it sounds like planaria. They usually come in when anything in the tank is being over fed or the water changes are not being done weekly. They could be there because you are feeding the snails. You don't want loaches because they will eat your snails.  The adding of the lettuce could also be bringing  on the worms. As is sits in the tank, microorganisms are growing. You can remove them by scraping the glass and removing any that you can. Some fish will eat them but as I have found out, not too many do. They will not harm the snails or any fish you put in the tank, they are just not lovely to look like. Try removing them, by scraping the tank and stop feeding the lettuce for awhile until the worms are gone. Also, make sure you are removing any waste produced by the snails, or you will not be able to get rid of the worms.