Liisa Sarakontu wrote:
I think that they are minnows (Phoxinus phoxinus),

Thanks for the ID. My wife suggested minnows, but I had in my mind that
they looked a little different. I did a quick search for them on
Google, and it does look like they are Phoxinus phoxinus. The only
thing is that many of the pics I saw showed red under the lower fins,
which ours don't have. Could this be something that will develop as
they grow, or is it an indication of another variation?

and unlike most Eurasian
wild fish, they are actually suitable for normal home aquariums. Small
(max. 10 cm / 4"), rather hardy, and should learn to eat normal flakes.

Oh it didn't take them long to get used to flake!! Within two days they
were coming to the surface for it. Now there's a food fight every time
I feed them!!

Glad to know they are suitable for the home. They make a pleasant
sight.

If you are still going to release them please do that rather quicky. Winter
is arriving and waters are getting colder. If the fish are now indoors in
warm water, it will be quite a shock for them to get back in their chilly
home water. Releasing them next summer will be ok.

I was only going to release them if they were going to grow too big.
Now that I know they will be fine in a home tank, I think we will try
and raise them. I was wondering about dropping a couple of ice cubes in
the water each day to try and keep it cool. It did occur to me that
being outdoor fish, they might find an indoor tank too warm. Do you
think I need to cool it, or will room temperature be OK?

They are in the kitchen, right near a sink, so regular water changes
are very easy. I have an air stone in there on a timer, so the water is
oxegenated for about six hours every night, and another hour or so
during the day. Hopefully that will keep them happy.

Thanks for the reply. Any further comments welcome.