On 05/05/2021 19:30, David wrote:
The tadpoles hatched from the frog spawn and looked pretty lively.

They were decanted into a plastic tub full of rain water which was buried
in the ground to form a mini pond.
Some bricks were added to provide a platform for mature froglets to use to
escape.
Plenty of pond weed for food.

Move on several weeks and it is hard to find any tadpoles, and those
located are still tiny and are not moving.

They are carnivorous and if there is nothing else to eat will eat each
other. Try ants eggs, live water fleas or fish food flakes to fatten
them up. It is so cold right now that I expect they are almost in
stasis. We had snow on the ground this afternoon and on Saturday.

I don't expect this year to be any good for plums, pears or cherries -
they have all taken a battering in the past couple of day. Hardly any
flying insects either. Swallows and house martins were wise to be late.

Internet searches suggest that one reason could be very cold water.
It has been very cold this last month with air frosts nearly every night
and it was a very chilly April, and May isn't looking much better given
the sleet and hail.

Has anyone else had problems with tadpoles growing?

Water seems fresh, there is algae and water weed for food.

I think they want a bit more than rabbit food.

If not the cold (and the water was screened for predators and a Mayfly
larva evicted to another tub) are there any suggestions as to likely cause?

My guess is shortage of food leading to cannibalism.

--
Regards,
Martin Brown