I accidentally fished some Newt eggs out of my Grandads pond when I was getting some pond weed, 3 have hatched into larvae out of 4 eggs (so I'm guessing this egg might not hatch) and I plan to raise them to adulthood then release them back into the pond.

They're about 0.5cm long, definitely Newt larvae, can't tell which species yet but wanted to know how to feed them because they've eaten their eggs and they're too small for anything I have currently. I have no Brine Shrimp hatchery or anything like that and they look too tiny to eat it anyway. I've done a bit of research but there really isn't all that much info on how to raise these things... One site said they eat pond water (I assume they meant the stuff in it) but then another site said 50% water changes every day! There's a lot of conflicting info but I have on hand frozen Rotifers & Cyclops which I'm hoping they'll eat when they're big enough, I have a large selection of frozen foods and regularly buy live food too. I have fish fry food but they aren't touching it...

So should I dump in some of my grandad's pond water? Also, about how old are smooth or palmate (most common in uk) newts before they undergo metamorphosis? How do I change their tank setup when they do? Do I just buy a floating thing like turtles and crabs have...? The sites I've been on are pretty vague...