Spontaneous generation in fish?

I have a puzzle for you all.

Do goldfish need both mummy and dady fish to make new fish?


My watergarden has been growing along fine. We have a shallow pool for mostly plants.  A 4 or 5 foot deep but narow opening for the fish and water iris that is difficult for fish eaters to get in.  And one, something like 500 gallon giant pool for the lily pads.  We haven't set it up yet that the spillover intermingles between the pools.  They are close but don't share any water (this part is important)

Well, 2 or 3 summers ago, one of the fish from the deep pool got beached in roots of the iris and in a panic, i scooped it up wth my hands to get it back in the water.  Not expecting fish to feel so fishy, I got surprised and tossed him in the big pool.  Since then he has grown like crazy.  He is easily 10 times the size of the fish he left behind.  It's hard to tell in water, but he's at least ready to be eaten as a snack for two or main protine for one. About 2 or 3 inches wide and at least 10 inches long.  If he was a Koi fish instead of a gold fish, he would be well past the $600 mark.  How big do goldfish get?  Considering he was half an inch long and 17cents when I got him...

I always ment to get the other fish together, but he's so big now, I figures he would eat them.

Anyway, he...or possibly she... has been alone in that tank for a couple of years.  

Alone

The fish stores all closed and we haven't been able to find more feeder fish to add to the pools.  I had always hoped that the tank with five remaining fish would make more in their fishy way.  But alas, I think it's not going to happen.

So I'm feeding old orange giant goldfish, who lives alone, his koi food.  Watching him eat it by the dozen because he's so big.  He loves his food.

But beside him, or possibly her, hovering beside the tail, is a tiny fish.  I sware it's swimming like a boy fish courts a girl fish.  About the size of Bigs top (dorsol? shark?) fin.  Maybe an inch long?  Water makes size difficult to tell.  Far smaller than the fish from the other pool.  Not much bigger than one gulp from this guy.  Watching closely, there are more fish under the lilly pads trying to nibble at the food that is way too big for them.

I can't be certain they weren't there yesterday or all the days before as big is only just getting comfortable with me watching him eat.

I counted the fish in the other pond and they are all still there.


Possibly one
Now, people do donate animals to the farm when we aren't looking.   It's normally pet rabbits for the owels to eat.  But the water gardens have an 8 foot privacy fence and are hard to see if you don't know it's there.  I can think of maybe 6 people who know where the water garden is.

The fish are very dark colour like goldfish were when we got them.  Sort of calico wth hints of orange and grey.  They also aren't quite the right shape for gold fish like we got before.   Probably gold fish or gold fish family.  Maybe.   I need to sit there with my camera and try to get some photos as they move pretty fast.

But there are nowhere to get goldfish in town now.  
None of these people would do something like this without asking first.


Possibly two
Lonely goldfish gets so lonely he/she makes more goldfish?

I know some ducks and frogs can do it.  For some reason i read in a book when I was a kid, I firmly believe fish cannot.  Can they?

Possibly three
?
Some other strange and crazy thing?  Bird brings fish from far off pond? Fish eggs came on plants we bought years ago when setting up the water garden and only started growing now?

From the wikipedia page on fish reproduction

Parthenogenesis is a form of asexual reproduction in which growth and development of embryos occur without fertilization. In animals, parthenogenesis means development of an embryo from an unfertilized egg cell. The first all-female (unisexual) reproduction in vertebrates was described in the Amazon molly in 1932.[33] Since then at least 50 species of unisexual vertebrate have been described, including at least 20 fish, 25 lizards, a single snake species, frogs, and salamanders.[34] As with all types of asexual reproduction, there are both costs (low genetic diversity and therefore susceptibility to adverse mutations that might occur) and benefits (reproduction without the need for a male) associated with parthenogenesis.

Parthenogenesis in sharks has been confirmed in the bonnethead[35] and zebra shark.[36] Other, usually sexual species, may occasionally reproduce parthenogenetically, and the hammerhead and blacktip sharks[37] are recent additions to the known list of facultative parthenogenetic vertebrates.

A special case of parthenogenesis is gynogenesis. In this type of reproduction, offspring are produced by the same mechanism as in parthenogenesis, however, the egg is stimulated to develop simply by the presence of sperm - the sperm cells do not contribute any genetic material to the offspring. Because gynogenetic species are all female, activation of their eggs requires mating with males of a closely related species for the needed stimulus. The Amazon molly, (pictured), reproduces by gynogenesis.

That's my first instinct.

And yet, google seems to believe goldfish can't survive to hatching, even in perfect conditions, without both parents.

And also, if it was a salmon, I would think that one new fish was very much a male with the way he is courting big orange. Swimming next to the poop hole and doing his quiver dance.

But, I need to get photos. Maybe I didn't see it right last night.