Dragonfly larvae in indoor tank?

I've now pulled two dragonfly larvae out of my 10 gallon guppy tank!
One a few months ago, and one this morning. I'm not pleased since I'm
trying to breed the guppies for local shows and cash. For those that
don't know, dragonfly larvae are predatory and eat small fish like young
guppies. I also think they're just plain creepy. I've never seen one
in a fishtank before - only ponds.

Does anyone know how the heck dragonfly larvae could even get into an
indoor tank? I haven't seen dragonfiles in the house and the window near
the tank is screened. I haven't added any new plants or fish to the
tank in months. Could the eggs have come in on plants and survived a 20
minute permanganate soak? Also, do dragonflies lay eggs in clutches?
If I've found two larvae, are there likely more hidden in the thick mats
of baby's tears along the back of the tank?

Finally, I know this sounds silly, but do they bite? I used a net to
fish out the one I found this morning because I wasn't sure about
touching it.

--
Elaine T __
http://eethomp.com/fish.html '__
rec.aquaria.* FAQ http://faq.thekrib.com