I think that Allan likes to see people continuing his work with Paros in Britain. For he did it for many years with great success and it ended abruptly. It’s really a pity for the British Paro scene (and the continental, too)!
Surely, the filter sponge will produce quite a lot of edible organisms for the young fish.
As the California brine shrimp eggs are concerned, it’s the same with me. First the other can must be emptied fully, then I shall continue with them. In onr or two weeks you young Paros will be able to feed on them.
And even your problem with the vinegar eels reminds me of my own. Only lately I learned two methods which might be conveniant.
I know the first from Paramecium; it does work with vinegar eels, too. Fill the eel-loaden vinegar in a bottle with long narrow bottleneck (or breed them there already)so that the narrow bottleneck remains partly free. Then put a pad of cotton-wool in it with contact to the vinegar. And then fill the rest of the bottleneck gently with water. Two hours later you can harvest the eels by a pipette and feed them to the fish.
The second method is similar to the harvesting of micro: use a small amount of yeast in a bottleneck to attract the eels. After a while they creep out of the vinegar on the blank insides of the neck. You can harvest them with a fine brush.