Blackworms, being blackworms, crawl through meshes they really shouldn't be able negotiate and can accumulate in the bottom of the box along with a certain amount of debris. So while the cold faucet is run (to clear any heavy metal out of the vicinity), the mesh (with it's inch and a half plastic frame) is lifted out and the box gently decanted into the toilet to wash dirt and debris out while keeping the live worms there. The worms remaining in the bottom are poured back through the mesh. The box is filled up with cold water and the mesh slid back in. It is quick, efficient and the worms get rinsed without drying out.

For images see:
http://www.aquaticfoods.com/blackwormcare.html
http://www.waynesthisandthat.com/blackworms.htm

I've done that 100s of times. A newly purchased batch of worms should be rinsed several times in a gallon jar. The worms are allowed to settle and most water and debris should be decanted. A turkey baster can snatch up items which don't wash out easily. Then it is wise to let the newly purchased worms sit and be rinsed a couple more days before they begin to get fed. After militant rinsing and water changing the first few days, the rinsing can coast a little. Worms so kept can last a couple of months.

Considering how chlorinated or chloramined tap water can be, it is gratifying how well the worms take rinsing. Leaving them out in the heat for very long, can be fatal though.

Some people who have trouble walking and chewing gum at the same time should not rinse worms while engaging in an animated conversation with someone in the next room.  A faucet was turned on to clear any dissolved metals. The worm box was emptied, filled and the worms quickly and efficiently dropped back in.

It was at that point that this correspondent realized that the water running was hot. Wrong faucet! The worms were raised from the box moments after they were placed in the water. Too late! The several 1000 were all dead (except for three individualists who had crawled between the mesh and the plastic frame surrounding it).

Soooo...
The worms were rinsed off a couple of times because some bleeding had already taken place. While they would soon spoil, there was a lot of protein there and why not feed as much as possible to the fish?

It is disappointing how some fish will ignore even blackworms if they don't show any movement. A few species or individuals are always that way, but it was a surprise how blasé even many livebearers were about limp worms.

A small quantity of worms were withdrawn from the worm holder, rinsed again through another mesh and put into a half pint pickle jar of clean, seasoned water. These were carefully dropped/squirted into the tanks. Placing them in the outflow of a powerhead or letting a few settle down right by the residents of a tank usually elicited a feeding response.

It felt more like delivering a fishing lure than feeding the aquarium fish. In a couple of annoying cases the worms were overfed and eventually ignored. Their capacity to foul the water is frightening and uneaten ones had to be siphoned or "bastered" out.

It was while sitting on a stool watching some golden lyretails clean the glass bottom of a tank about 4.5 feet up that an interesting pattern could be seen through the bottom glass. The males were gathering worms as they dropped down the water column. The females gathered at the bottom. One robust female ate first. A skinny one was always last to gather food. The pecking order at work.

Slim would make a move at a worm. If the dominant fish went for it, she would back off. In time she would make a hesitant motion and the others would let her forage.

In a number of tanks the first dollop of worms led to a general feeding frenzy. Then dining was in a more prescribed manner in several tanks.

In a 40-gallon rainbowfish tank, a few worms at a time were dropped in the outflow of the powerhead/ sponge filter combo. Rainbows are notoriously unwilling to go down very far in a tank to feed. Live worms elicit enthusiastic feeding. Dead ones stuck on a branch were ignored until they were knocked loose into the current again. A small smiling cichlid (Laetacara curviceps) is allegedly on bottom cleanup duty.

Three turquoise rainbows (Mel. lucastris), a dwarf neon (Mel. praecox) and a Glossolepis multisquamatus made up the staff. A six-year-old turquoise is dominant and the multisquamatus is least dominant. Ol' one eye always got first shot at the worms. The other lucastris and the praecox would coast in the current behind him. The multi played backup. As the front fish filled up, the backup worked his way through the pack. When every rainbow had his fill and some had sailed enough to the little curviceps, it was interesting watching the multisquamatus. He unfurled his relatively larger fins and began displaying. When numero uno also stretched his unpaired fins and began dancing, the kid ("Hey I'm full too!") displayed opposite of him. They were so stuffed they didn't bother to chase one another. ;)

In the meantime in the Girardinus metallicus tank, the big mama always got her way. Her diminutive consort was way behind her in power points and the 1 & 2 month old fry way behind him.

Elsewhere the big females of Limia perugiae almost always got their way, but those disrespectful little juvies would grab a worm and take off whenever the chance offered. The big girls or one of the two big males would catch up with the squirt, grab the worm, give it a flip and inhale it because the youngster had decided to go elsewhere.

It's got to be tough being on the wrong end of "crack the worm."

When two like sized youngsters each grabbed a blackworm, it got interesting. Several times they bit/ broke off a piece and settled for that.

That reminded one of a recent speaker (Rosario LaCorte) who recommended slicing up live worms so the young fish could more conveniently and efficiently chow down. Out east in New York or New Jersey a multi-bladed veggie slicer shows up from time to time in kitchen sections of stores. Hitting black worms with what essentially is a five bladed pizza cutter prepares food for the kids pretty quickly.

Elsewhere in a grow out tank of bivittatum (Aphyosemion or Chromaphyosemion, take your choice) smaller worms were swirled out of the mass and dropped in. "Bivs" will feed from the bottom, but are much more enthusiastic top and mid-water feeders.

When he wanted to, the biggest male would swim to the feeding area and take what he wanted without too much competition. A couple slightly smaller males were followed by several females. The two smallest fish in the tank carry the juvenile/female color pattern.  Their gender is still uncertain. After an hour of off and on feeding, the big boys and girls let them in. They filled up last night, but I think they will have to be removed to their own quarters. Otherwise the larger bivs will continue to get disproportionately larger and larger.

Found some fairly full Fundulus under wads of Najas. Worms dropped 2 cm from their noses would get eyeballed. Then some one would slip out and spaghetti suck a worm up. Straight size seemed to be the index after the initial frenzy.

Eventually over half the deceased annelids, still not fed, were flushed. My luck with freezing them has been checkered and sometimes discretion is a wise thing. Despite careful feeding, one 5-gallon tank got too many and since it was over due for a tear down, got torn down today.