Help me please! Ergent!!!?

I found little white poppy seed like specks in my 20 gallon fish tank this morning. At first i thought it was pygmy cory eggs but i only have one cory and the specks are crawling all over the tank walls! I have about 20 baby platties and one pygmy cory in there. And if it makes any difference i have 23 guppies in there too but i took them out yesterday to sell them. Please help because i think they might be a water bug or something!!