Worms!

Unfortunately somebody in our lab, while he was for some reason gazing at zebrafish feces earlier today in a petri dish, noted some creepy-crawly worms playing in the dung.

This is bad news, as these are nematode worms, a parasite which can infect fish (as well as mammals).  So now we have to quarantine off a bunch of fishes (fortunately none of the ones that I have been using) and treat with antibiotics until the infection is eradicated.

Another example of a nematode worm is C. elegans, a very popular organism for studying development and genetics.