Tadpoles and your fish

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There are tadpoles in my dam, and some of them are small black tadpoles.
Are they cane toad tadpoles?
Will they hurt my fish?
I have been asked these questions many times, the short answer is - NO they don't seem to hurt the fish.
Small black tadpoles are almost certainly *cane toad tadpoles. *(Bufo marinus)  
They are usually seen along the shallow edges of a dam in large schools.
They school up to increase the chances of survival. schooling tadpoles
 
Cane toads were introduced to Queensland in 1935. 
Of the approximately 100 toads released, the population grew to an estimated 60,000 within six months. 
They are now ranging from New South Wales, to Western Australia. 
In 2009 they reached the Western Australia border.
They are advancing south at about five kilometres per year and west across Western Australia at about sixty kilometres per year.
 
My ponds were not protected from cane toads so there were always thousands of cane toad tadpoles and eggs in my ponds, during the warmer months of the year.
When we harvested and scooped up the fingerlings from the harvest net, or the harvest sump, the cane toad tadpoles were in the net along with the fish.
At no time, over almost 40 years, did I ever see any evidence that the eggs or tadpoles harmed the fish.
Also, I served as president of the industry association for decades, during this time I have never had any other hatcheries or fish farms mention any issues with cane toad tadpoles.
Air farm 2004
I produced many, many millions of native perch, (Silver and jade perch.) Australian bass, sleepy cod, barramundi, Murray cod etc, with no losses.
Plus many varieties of exotic fish including platies, mollies, guppies, swordtails, goldfish, danios, angelfish etc, and I never experienced any evidence of cane toad tadpoles or eggs harming the fish.
Also of interest is that I produced many kinds of other Australian native fish in my ponds.
Most small Australian native fish, including rainbows, blue-eyes, gudgeons, even coal grunter and archer fish.
Harvesting small ponds
However all life stages of cane toads are toxic to fish.
If fish consume the eggs or the tadpoles they will die.
I NEVER saw any evidence that my fish were killed by cane toad eggs or tadpoles, or the baby toads.
This includes any dead fish around my 127 ponds and 4 water storage dams, or in my holding tanks, or transporter tanks.
I did not conduct any research into this as it didn't seem necessary considering I was not experiencing any issues.
 
Conclusion - stocking fingerlings in farm dams when there are cane toad eggs, tadpoles, or toadlets around does not present any threat to the survival of your fingerlings.
The assumption is that the fish for some reason, did not consume the eggs, tadpoles, or toadlets.
Perhaps each life stage of the toads has a bad smell, or perhaps the fish tried them, and they have a bad taste so they spat them out.
 
In fact, if you dig deeper on the internet this idea is supported. 
The Science Insights website says,"Toad tadpoles produce toxic compounds in their skin that make them deeply unpleasant for fish to eat.
These toxins are potent enough that many fish learn to avoid toad tadpoles entirely after just a few encounters . . .  This chemical defence gets stronger as toad tadpoles grow.
Research on cane toad tadpoles found that newly hatched individuals were somewhat unpalatable to predatory fish, but late-stage tadpoles approaching metamorphosis were completely rejected.
The toxin concentration in their skin increases as they develop, making older toad tadpoles essentially untouchable." 
In June 2008 a report released by the Northern Territory Department of Agriculture and Fisheries says, "There is no evidence that cane toads have caused a decrease in fish numbers."
Wikipedia says,"Avoidance of cane toad tadpoles by predatory fish. 
The toxins present in cane toad tadpoles are concentrated in the skin.
Therefore, mouthing of a tadpole is sufficient for most predators to detect its toxicity."