Feeding Grindel Worms To Fish

I have a long established (almost 10 year old) 40 gallon freshwater tank
stocked with an assortment of fish, most of whom are around 4 inches long:
a red-tailed shark
a dragon goby / dragon eel / whatever the name of the week is
he's much larger - about 8 or 9 inches long
a tiger barb (or possibly a clown loach, my money is on the barb)
an assortment of 5 or 6 platys (look like minnows)
a big silver dollar fish

(I'm not 100% on some of the fish types as I was in Canada for the
purchase of most of them)

The tank is equipped with a dual-powerhead undergravel filter, a box
corner filter, an air-stone bubbling away, as well as a 20 W hood
providing illumination.

Now these fish are being fed on a mix of the typical flake food stuff and
a frozen mix of well, bits of all sorts of stuff we get at the store,
which is intended primarily for the dragon goby - not that much really
ends up down on the bottom for him.

It has long been my intention, from when I first got the tank seven years
ago (used, complete with fish (not, unfortunately, the same fish), gravel,
hood, pumps, and background) to feed them a varied diet - and for a while
shrimp pellets were added to the flakes. Moving to a live food supplement
has always been on the back burner, but things like moving to Canada
have interfered over the years

Now that I am unemployed and back at the family residence (with lots of
time on my hands) I have been looking into feeding live food as a
supplement to what they're getting now. Partly because it's something
else to grow, and partly because I feel that if the dragon goby has
something besides his fishy friends to eat he'll eat less of them (as
family members swear to have seen him do).

Perusing the various live feed faqs and web sites it seems that
maintaining a culture of grindel worms is both simple enough as a first
trial run that even I probably won't screw it up, and not too invasive (my
family is going to protest vigorously if I have worms in the fridge. I
don't even have to ask. Storing the frozen feed mix in the freezer was
challenge enough).

Ideally the fish would be fed a few worms every day (probably in the
morning, as their normal feeding is at night) as a dietary supplement and
diversion from the usual swimming in circles.

However given the size of the fish in our aquarium, I am not sure if the
grindel worms are even going to show up on their radar (sonar . It
would be a shame to have to tear down the tank because I fed them a bunch
of worms they wouldn't eat, which then proceeded to burrow into the gravel
substrate and expire at some later date.

So, oh sages of the net, is this a good idea? Or are my culinary
offerings going to be spurned by my fish?

Alternatively, would Daphnia work? I have a small tank languishing away
in storage I could convert to a daphnia hatchery (maybe with some plants
and a snail or two - which might happen anyway).