i was doing a water change today in my 55 gallon. as i was dumping the water out i noticed stuff moving around in the gunk that didnt go down the drain yet. at first i thought they were little bugs but when i picked one up it didnt have the exoxkeleton feel of an insect. i guessing they might be fry? i have zebra danios, bolivian rams, black neon tetras, and one male molly. i attached a drawing of what they look like, and they are aproximetly 4mm long. are black when looking on top but almost clear from the sides. thanks