Also, and I think you know this, for the benefit of friends and visitors looking on, freezing may cause some of those shells to break. That means that a certain amount of "organic soup" (which sounds better than shrimp juice and blood) will be in the Luke-warm water you used to defrost it.

Rinse it through a fine-meshed net or a sieve. Maybe verrrry gently let a little clean tap water rinse it and then put it into a jar of clean water and use the turkey baster (dedicated to the guppies) to feed a little at a time.

At least one female correspondent here suggested using a scrap of nylon stocking. I could miss-remember this, but I think she put it over a jar loosely and rubber-banded it in place.

Since I'm not wild about doing extra water changes to get that juice out or to pick up uneaten (rotting) b.s. in a tank, I am keen on rinsing the frozen food and gradually feeding so very little is left. One or two pond snails (I know - try telling them ONLY TWO!) are very valuable in cleaning up scraps.

If you suddenly get a ton of pond snails, guess who is overfeeding that tank? ;)

Velvet organisms (like many other diseases like Ich, fish TB and various bacteria) may exist in the water column at what Terry Fairfield calls a "non-lethal concentration. Having rotting b.s. in an aquarium can cause a bloom in the numbers of velvet (Oodinium or Piscinoodinium) and they can overwhelm a fish's immune defenses. I hadn't heard of guppies getting velvet until hanging out here. It happens though and the fry, sometimes with pointy tails, may go very fast.

It is more common among Bettas, other Anabantids, rainbowfish, killies and even suckermouth catfish (in the gills where we can;t see it.) There is some in Immediate Help and Googling Guppylog for pointy tails, velvet, Oodinium or Piscinoodinium will get you more info.