It's ALIVE?!?!?

Earlier today, I went through my normal routine after I get home of feeding my fish (frozen bloodworms for the darters and sunfish, flakes for the mollies and platies, algae wafer for the pleco, though everyone "shares" a little of everything... ). Just a few minutes ago, I went down to turn off the lights for the night, and I noticed a few little trails through the sand at the front of my tank. Upon closer inspection, I realized they were some of the bloodworms! (?!?!?) Of course, I immediately dug them out so my big male fantail could eat them (YUM!). (He's my little buddy, always watching me, follows my hand around when I'm agitating the sand, etc.....)

I didn't know that bloodworms were frozen alive, never mind surviving a rapid defrosting???? I guess I could see the application of this ability in nature, but it's still kinda freaky. (Mosquitos loose in MY HOUSE...... )

Anyone else encounter something like this?????

I would guess that most likely the critters came in with something else. I have loads of inverts that have come in hitchhiking on plants. If you got any stream water in the tank, larvae could have come in that way too. Or just stuck to a fish. Although, I once got tubifex worms in a tank at college that had store-bought gouramis and was only fed flake and freeze dried food. Have no idea how that happened.

I had daphnia hatch from frozen food once. I guess that's kinda the same.

"Bloodworms" are the aquatic larval stage of flying insects, and probably don't burrow in substrate. But something else may have come in the frozen material, like eggs, and hatched out as Irate described for daphnia.