"newsb" wrote in message
...
In article , BAC
writes


Maybe it is and he hasn't noticed them - tiny black fish can be difficult
to
spot. Maybe it was and most have perished. Of course, there are lots of
possible ways a 'stranger' may have been introduced, but they are all
less
likely than some normal spawning activity amongst the original residents.



I'm not suggesting this happened in this case, but 2-3 years ago, my
mother in law discovered 20 or 30 baby goldfish in her pond. As they
were getting eaten, she fished 10 out and put them in some of her indoor
aquaria. They were silvery with a hint of gold. Over the next 2 years,
they stayed silvery, causing us to wonder if they were really goldfish.

A coarse fisher that visited asked what we were doing with dace in the
fish tanks. We were very puzzled - wondering if a visiting bird maybe
dropped some spawn - and other unlikely things.

Eventually, we recalled that in the year of their appearance, we had
gone to a local stream and my daughter had collected some "frogspawn".


Well, assuming that the local stream has a population of dace (they prefer
relatively fast flowing water), it is not impossible that they may have been
inadvertently transferred by your daughter. Dace spawn in the spring,
usually between March and May, and deposit their eggs on sandy or stony beds
or on aquatic plants. The eggs hatch out after four weeks or so.

Frogs, OTOH, can spawn at any time between December and April, depending on
the weather, and usually choose shallow, still water to do so.

So there is a definite possibility of someone 'dipping' for frogspawn in the
margins of a stream (although dace prefer fast flowing habitat, they usually
drop downstream to slower water to breed) in March/April picking up some
dace spawn, especially if they transfer weed or stones to which spawn may be
attached.