Does anyone know what they like in terms of water etc, we have some in the river, I'm thinking of keeping them in the pond or tank?

Things I am wondering about include: are they ok in soft water, what temperature should they be kept etc.

I don't know about the fish but they live in your local river then... why don't you test the water and see the environment that they fit in? =D

Normally test the water at the time they appear the most so it'll be more accurate =D

Is it legal to keep fish from a river in a tank?

According to Fishbase they need hard or brackish water, pH 7-7.5, dH 10-20, temp 2-20C.

They also need very well oxygenated water and a good current - stream/river bed type set up.

HTH

Yeah, as long as they are not threatened, lots of kids catch minnows right? I used to catch little fish as a kid and add them to our pond.

Thanks Noodle! :)

As far as I know it's still OK to catch Minnows at the moment - not true of all native species though and should always be checked with DEFRA if in doubt as the regulations are subject to change. I believe it is not legal to return them to the wild afterwards though. If you remove them to a pond or aquarium, they have to stay there.

Yeah, that's what I heard- no returning them to the wild.
I had checked fishbase, but must have missed the parameters- there is a link to an aquarium care on it but it didn't work for me.
I wonder what do they eat? Would flake be ok?

I didn't click the aquarium care link on there as they usually don't work!

Wild caught ones may be able to be coaxed into eating commercial foods eventually but would initially need to be fed live foods and algae - crustaceans, insects, bloodworm etc.