Peat moss, just spray some water on it, don't get it too wet, the worms just need it lightly wet. topped with newspaper there's where the food is offered don't let it get to the peat moss so it won't foul the moss quicker, the moss can be replaced every 6-8months. But right now because my brother just got a dog I can't really raise any worms so I just collect em in a near pig farm of my uncle's, pretty much I don't have to cultivate them on my own, I harvest for 4 months daily already and it seems that they're still a million in numbers to me. But for the worm you're getting you won't really have that time to wait for them to cultivate, you do have to make it more and wait for 1-3weeks or so in order to make them cultivate on their own. The feedings is every 2-3 days, just replace the newspaper every other feeding then that's that. Don't let it be under direct sunlight, make sure it's just near to room tempt, extra 2-4 degrees for faster metabolism, just wait for a month or so and they'e reproduce a stable amount, that's like 10-15 earthworms a day would be enough as everyday's harvest, chop em up/ offer them live, and make sure that the container they're in is not that clamped or there will be no escape for their excreted gas which may turn up to ammonia when some worms dies make sure to toss it as it may foul the peat moss. It's my own experience were talking about and I have no problems regarding raising them.
+advice make sure you're gonna offer some peas for the fish, a earthworm may end up bloating your fish, so a little 'poop helper' is needed.
+advice make sure you're gonna offer some peas for the fish, a earthworm may end up bloating your fish, so a little 'poop helper' is needed.