[Pavel Chaloupka]

Yes B) thats what they are exactly. Bloodworms or Chironomus larvae if you want. Great food for most fish including Paros and whats more, they do not bite when they hatch inside. They form little tubes out of detritus on the bottom, so if you are able to spot small eleongated structures, if you gently loosen them from the bottom and put them in to a sieve that touches the water level, the bloodworms will go trough the sieve in to the water again. This way you will get clear bloodworms for feeding. There is probably much more of them on the bottom of the buckets than just these that you were able to spot. Bloodworms can even be cultured indoors.