So I changed my filter yesterday and discovered the bio grid had what appeared to be slime worms "blowing" out from the filter, I took it out and rinsed it off and thought it was just algae or something. While I was doing other things, the filter was left sitting in a basin overnight. #3 son was up all night cleaning (he's on prednisone for poison oak), picked up the filter to throw it away and found a basin full of little white worms. There are only a few worms left now (I am guessing they went back to the filter) but they are tiny, white, and have a dark head. From my reading this forum I am guessing they are planaria or nematodes (same thing???)...don't know how cause we give the fishes food and watch them clean it up and stop feeding when they stop eating. I did feed a bit more yesterday cause I brought home 3 corys yesterday and wanted them to get some food. Guess I should just get something just for them that will settle to the bottom? After that horror, I went to look at my new babies and could only find 2 of them. #1 dtr found the third...attached to the intake of the filter...When I went to remove him, he appears to be breathing but he is definately NOT right. Is this what I get for buying fish at Walmart or is there something more wrong? Everyone else seems happy and content...one of the corys (who does not have the same markings as the other 2 - is that a problem?) is absolutely crazy, darting all over the place, up and down the sides of the tank (vertically), and the other though not as hyper is swimming along merrily. The danioes are their usual hyperactive selves, and the tetras are just swimming around lazily (like normal - they rarely get excited unless there is food in the tank!). Water parameters prior to water change yesterday were pH 8.2, ammonia 0.25, nitrite 0, nitrate 40 ppm...getting ready to check today to see if something went terribly awry! So, my questions: are these things related? Do I need to feed less? Guessing I need a gravel vacuum now..was avoiding for now cause I have NO idea how to use...Is there something more serious wrong??? Thanks for your help!