little white bugs

Question
I have a 55 gallon tank with two Oscars and a algae eater. I have been noticing a ton of little white bugs, to me they look like little nats, I've seen them flying around the tank, you can see them best on the inside on the lids. I have tried taking the tank completely down about once a month and cleaning everything. And the bugs return, just yesterday I vacuumed out the gravel and half the water. And today the bugs came back again. What are these? Are they harmful? How can i get rid of them?  

Answer
HiYa!

It sounds like it could be Planaria, which are small flatworms that generally arise in a tank due to overfeeding and excess waste.

You say you have recently cleaned your tank very thoroughly, so my next suggestion would be maybe keep an eye on your feeding levels, do a couple of 25% water changes over the next few days and see how you go!

Hope this helps!

Cheers! Rach