As ever good advice, I think this was exactly what happened to the Dicrossus maculatus in this thread: <http://www.apistogramma.com/forum/index.php?threads/1st-d-maculatus-spawn.12389/>.Also note that all worms have a higher fat content. They should be used for conditioning and occasional feedings. Otherwise your fish can become obese and have shorter lives - just like people!
I think you should be able to get them from sellers of live food for reptiles, and you may be able to get Dendrobaena (Eisenia hortensis) as a fishing bait worm, they sell them as "European or Belgian Night Crawlers" in the USA.Thanks Darrel, the worms I was about to order were the fetida. I do not see the tastier worms offered for sale anywhere?
The iridescence bit definitely sounds like Lumbricus rubellus, definitely dark red with a purple blue sheen. I don't know if it would help, but I've got a lot of plant pots on my patio, on slabs around the garden etc. and I've found that if you look underneath them (after a couple of wet days) 99% of the worms you find are L. rubellus. You need to grab them fairly quickly as they become very active as soon as the light hits themThe red ones that seem to work best as fish/herp food are a bit more iridescent than the others, so L. rubellus might be it.