"jw 1111" wrote in message
...
Hi, have a tank about 4 ft x 3ft x 3ft in the garden in north london u.k.
it overflows into a much smaller tank. last year i put two goldfish in
the large tank. later small black fish appeared in the small over flow
tank, but interestingly none in the big tank. (guess all the eggs must
have flowed into the small tank) i am wondering why no baby fish appeared
in the big tank though?

They could have eaten all the eggs or fry. There may not have been enough
plants for the young fish to hide in and find small enough food to eat.

recently i took a few of these babies out of the small tank and put them
in an indoor glass tank. a couple of these have turned gold colour, but
the ones outside still have stayed black even though they are bigger than
the ones taken inside. why is s this would you think? what in fact
determines when they change colour?

Good question?!?!?! I *think* it's mostly genetic.
--
Koi-Lo.... frugal ponding since 1995...
Aquariums since 1952
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