minnows in aquarium

[carey]

In august i acquired a collection of minnows and water snail taken from a stream by my grandaughter.They survived long enough for me to to put them in a small aquarium.[i wanted to return them to stream but it was to far away]


they have survived remarkably well ,lost about 3. until yesterday there were 6.

today much to my surprise there are now seven. there were definately only six yesterday. the new one is more than half inch long.
What i am wondering is why there has been no sign of it before,and it suddenly appears at this size.i check numbers daily .the only thing i did notice was that one of the six was not always visible in the last few weeks.
does any one know details about breeding habits,as it appears that it has been nursed and hidden til it reached certain size.[water snails also multiplied and have only just become evident]

Carey.

[Ukwildlifeo]

It might be that the minnows spawned and most the eggs/fry got eaten by the adults, but one particularly wary fry stayed hidden (do you have many plants in the aquarium?) until big enough to avoid being eaten.