At first not knowing what they were I did some research, I came across the usual suspects (planaria, nemetodes ect...). After ruling these out I started to look at what I was knowingly introducing into my tank ("frozen" brine shrimp naupli and cyclops). I was gobsmacked...


Over the weekend I caught some of these little critters and took them to my LFS who confirmed that they were indeed cyclops (the Y shape of the female gave it away). An apology and a ten % discount later... I felt quite smug.

Knowing this, how is it possible that they got into my tank? And can they be resurrected frankenstein-style after being frozen?
I have looked for logical explanations and so far none have come to my attention.