Red creatures caught with gammarus

I was collecting gammarus from an old half-barrel in the garden today for my aquatic newts and was surprised to see hundreds of bright red daphnia-sized creatures coming up in the net. Through a magnifying glass they look similar to daphnia--is that a winter colouring for them? Or is it some other water bug? I didn't put them in the tanks.

I also collected a good dozen common frog tadpoles from the same source which result, I presume, from the spawn I dumped in the barrel last spring when an old plastic duck pond had to be removed. I know some of the frogs morphed last Summer because I caught a few and fed them on springtails as the weather was cold. Today's tadpoles are about a centimetre across, with a full tail, and no sign of budding legs back or front. Will the lower temps last Summer in the UK have caused slower growers to become neotenic tadpoles?

Sorry, no pics.

If they look like Daphnia and move like Daphnia then they are probably Daphnia (seriously). They can be quite reddish depending on the food source.

As for your tadpoles being neotenic, I would think it's more likely they haven't gotten enough food and/or they have been cool a long time, both contributing to slow growth and metamorphosis. It's more likely that you'll find a pot of gold at the end of the rainbow than that you would make a single neotenic tadpole of any English frog species.

-John

Has there ever been a documented case of a neotenic frog?

Thanks, John--I'll keep chasing the rainbow! I find it hard to believe there was insufficient food. It has been there for years before we bought the place and it contains four sorts of water plant, a thick layer of rotting leaves on the bottom and abundant pond life. The water is like soup. I know the diets are different, but all last Summer the barrel was full of adult frogs, three of whom never left until October.

When the tadpoles--given adequate temperatures and food--do morph, will they do so earlier than usual, or will they wait 'til the normal time?

I know this is an old thread, but I thought I would add that other contenders for your bright red bugs are calanoid copepods and water mites, both of which include several red species and are similar in size and shape to daphnia.