Red Wigglers okay? Oops, typo

Question
QUESTION: We have a 120 gallon freshwater tank and went through a long spell (many months) of very cloudy water.  I also have begun keeping a compost bin with red wigglers.  Hmmm, I dropped a worm in to see what the fish would do, and they tried to eat it, but it got away and wiggled under the gravel.  I have since dropped in a few, maybe a couple per month, and they also make it to be bottom and disappear.  Coincidently (or not??) our tank is not crystal clear.  Do you think the worms had anything to do with it, or was it just hubby's diligence in water changes?  Also, when suctioning the gravel yesterday, there were several (3-4) intact worms that got sucked up from the corner of the tank.  I was very surprised that they had not disintegrated.  Do you think they could have been alive under the gravel??  And most importantly, could I harm the tank if I continue to drop a worm in now and then?  Thanks!!

ANSWER: Hi there!
Its a great thing to offer your fish live food. Being very beneficial to their health and offering them something to really entertain themselves with than just boring flakes or pellets.

The fish (Depending upon the size and species) should have gobbled up the worm unless it is either too large for them to swallow, or the worm simply gets away too fast and burrows under the gravel as you have noticed.

I actually am not sure how long the worms can survive underwater but I'd imagine less than a few days. When they do perish, their bodies are decaying to some extent in the gravel and adding to the bioload. Since the water was cloudy some before, sounds like this aquarium might need a few more large water changes than what it is getting at the moment to keep up with the amount of waste being produced.
The wiggly worms are perfectly fine to feed, just try to make sure they don't get lost in the gravel. If you have any medium size catfish species in the tank he'd take care of your *worm lost in the gravel* problems.

I hope this helps!
Karen~

---------- FOLLOW-UP ----------

QUESTION: Oops, after I sent my question, I noticed a typo.  I meant to say our tank is "now crystal clear".  Typo was the word not instead of now.  Sorry for the confusion.

It has been interesting researching this particular curiosity, I have found only two similar cases.  One was on this site where a guy had a "planted" tank and wigglers appeared in his soil level.  I would bet there had been cocoons in the soil he used and they grew and reproduced.  Sounds like in his case, they thrived.  Another worm farmer reported that he has seen live worms up to a month after their escape to the gravel.  Maybe there is enough aeration in the tank to support their needs.  

No question, Ijust wanted to thank you for your response.  I enjoy both my hobbies, the fish tank and the worm composting.  Thanks for being part of it!

Answer
Oh, no problem!

Very interesting info you found about the wigglers. Amazing how they can survive both in soil as well as underwater for quite some time, amazing feat being they are such 'plain' unadvanced creatures.

Thank you for your questions! Its always a pleasure discussing this hobby with fellow enthusiasts and I wish you the best with it and your worm composting! Its a wonderful way to get rid of unwanted vegetable/fruit peelings and in turn, get some great soil for gardening isn't it?

You're welcome and have a good weekend!