I think you mean tadpoles but Mosquito Dunks will not hurt the tadpoles. Bacillus thuringiensis subspecies Israelensis strain EG2215 is designed to kill mosquitoes and a few related insects only. Sandy

Thank you, Sandy!

Sandy, does that hurt Dragonfly Nymphs?

JP, I went back to the most recent Gov. requirements for reporting info on insecticides by manufacturers and by its stated conclusion BTi affects mosquito larva, blackfly larva and fungus gnat larva. It may have an effect on daphne but that is apparently too low to be included in the data.
In any case, potential harm to subjects other than the target are required on the package label.
It is also important to make sure you are using the correct BT for the target. There are several. For instance, BTk, Bacillus Thurengenesis kurstaki is the one used for control of catapillars and has no effect on mosquito larva. Sandy

Hi
I have a pond with koi and turtle(1), lotus and water plants etc. The reason I
am writing is to beg you to stop using those dunks. The Goverment information should be your last resource if you want to protect yourself and especially bee's. Much info is availabe online about these horrid dunks. I battle those bad bugs easily because I don't kill off or chase good bugs or birds away. If you have fish there is a remedy I can share with you. If you do not, I have that also. I also would research the dunks ingredients actives AND non-actives. You will be shocked that these poisons are banned from Military use around our soldiers due to toxicity. Consumers are another story which states in writing we were aware of said ingredient apon purchase. I went through 3 seasons of h-- apon stopping all chemical anything. I know what your going through out there. It was time to thank Mother Nature back I suppose. Please don't use them please. :(

Digginitup, can you please give me a source for your claim. I have never run across a reputable source that was negative. The advantage of BT products is that they do not contain any pesticides or poisons of any type.The bees were in trouble long before BTi came on the market. If you are correct I will be happy to retract my posts. Sandy

im not 100% sure but put a dunk out in my pond and within a couple of days my tadpoles were dead. it could have been something else but everything else was the same. my husband says that tadpoles eat mosquito larvae so not to use the dunks anymore.

I use mosquito dunks and have for years in ponds without circulation and the toads and frogs deposit the eggs in these still ponds, the tadpoles grow into adults and start the cycle again. Tadpoles do eat mosquito larvae. I'm sorry about your tadpoles.

I've been looking around because of a neighbor who has a water feature that infests the neighborhood every year. The tadpoles are a concern to us, as are dragonflies , birds and bees and from what I've been seeing the minimum doses are safe for them but the maximum dose had a 100% mortality for tadpoles after 48 hours. I'm still on the fence because we already have seen small swarms of mosquitoes and I wanted to toss the right amount over their fence as soon as possible, just kidding (kind of). I guess asking permission is the best way, then I'll have the proper measurements to decide the dosage.

I have been using Mosquito Dunks in my ponds and water features since 1997 and I have hundreds of treefrogs and dragonflies every year. Wildlife such as birds, squirrels, raccoons, opossums and the occasional cat drink safely too.

Yep, they eat mostly algae. Watch them sometime.

I wouldn't be too quick to say tadpoles won't eat mosquito larvae. It's a well documented fact that sometimes tadpoles eat other tadpoles. Happens commonly in arid areas where water tends to be ephemeral and tadpoles need to develop very fast before water evaporates. Eating other tadpoles is believed to reduce competition for food as well as provide extra food. What I've seen myself directly isn't conclusive, but I had 3 large tadpoles of Cyclorana australis in a container in a protected place. Ended up with only one (a very large fat one). In a container in my shade house I found a single tadpole of Litoria caerulea. I've never seen a female stop at laying just one egg, so I suspect that tadpole was the hungriest and fittest thus becoming a survivor. So I think it's feasible proposition that tadpoles could eat the much smaller mosquito larvae. But that said, I find that large containers with tadpoles in them sometimes end up with a lot of mosquito larvae as well. The solution I developed was to keep floating Utricularia plants in with the tadpoles. The plants eat the mosquito larvae as they hatch. I also have fish that will eat mosquito larvae but not tadpoles. There are a number of solutions.

A pond with fish won't be a source of mosquitos breeding. Mosquitos look for standing, still, stagnant water. If they do lay eggs in a pond the larvae will be quickly devoured by the fish. A water feature (no fish, just water), however, could breed mosquitos and dunks would be appropriate in that case.

Mosquito Dunks and Mosquito Bits are made from naturally occurring soil
bacteria called Bacillus thuringiensis strain israelensis (for the rest
of us: Bti). Safe for all except the bugs of target. Between Zika and a Dunk the dunk wins.

A fish filled pond can still have larvae. I found mine in a in pond Beckett filter box. Any plant out of the water where water can sit is a good place too. I have artificial water lilies on top and water collects in the leaves. Bet that is also a place I have to look at.

So, apparently, only larger species of (of frogs) tadpoles eat mosquito larva. The rest are mostly vegetarians.

http://www.wbrcouncil.org/Departments/Mosquito-Abatement/Natural-Mosquito-Killers

So to my understanding everthing but Mosquito larva is Safe, so if I buy fish to eat Mosquito larva too, will they be harmed by eating infected larva. And are these dunks “completely” safe for horses?

http://www.i-sis.org.uk/Commercial_Formulations_of_Bt_Toxins_Lethal_to_Amphibians.phpI

It is toxic!!!!

The link must have moved. It is no longer active.

NO! Don’t do it with any animals around! Kills them!

Kathy Durrum do you have any links or info to support this? My dogs cats, wild birds, snakes, and amphibiaians all visit a very shallow toad pond treated with dunks, and have for 5+years with zero issues. From reading the past comments it seems that you're advice is based on only your husbands opinion, but if you know of some info that is published Id love to read it as Im very involved with the wildlife here and if something were to be a danger I'd want to know.

We had it personally happen to us with our annual tadpoles. Since not using anymore they have reappeared

tadpoles eat only algae at first but develop teeth or such to begin eating bugs that drown. i have mosquito larvae and they dont persue them so added a bit of dunk. Suspect they may eat the dead ones but havent seen them. I start with algae fish food and then add beta food. They love the flaked food. Harder to eat the pellets i erred with this year.

I have not obseved any issues for my dog or cats and do see them drink.

My tadpoles are being very slow to mature, and i use mosquito dunks in the pond. the tadpoles hatched last fall and over wintered okay in the pond. now it is June the next year and they are just beginning to start rear legs and i saw one briefly come to the surface, perhaps to breathe. weve had this pond for about 20 years and ive never seen frogs develop so slowly! i feared the worst until i started seeing legs emerge from some. im wondering if the Dunks slowed down their emergence somehow. maybe just the weather, though though. the pond has been very slow to warm up this year, so i give the benefit of doubt to the Dunks.

It will KILL your frogs/toads!! do NOT use!! we saw it first hand in our pond

I have a moving water feature and have used the mosquito dunks which work for mosquitoes but then my water feature grows yucky brown green algae. Any advice on how to use dunks but not have algae? I heard vinegar is safer as u do have birds I. My water feature. I read also a post about putting pennies in the fountain. I would rather put an algaecide that doesn’t hurt animals

Angela Chen, if you have a store nearby that specializes in water features, or one for birds, they should be able to provide you with advice for the algae. At our Wild Birds Unlimited, we bought ”Bird Bath Protector” that is just safe enzymes to keep the algae down in our bird baths (although it does work better if you can start with a clean bath). I wouldn't add vinegar to water, since the quantities needed to kill the algae will probably harm other things as well.

As for the mosquito dunks, the last batch I bought says ”Bacillus thuringiensis subspecies israelensis solids, spores and insecticidal toxins.” Not clear if “insecticidal toxins“ are from the Bti or added separately to ”enhance” the killing, although I would think they'd have to list the exact chemical if a separate insecticide is added.

I think the comment about dosage and tadpoles is crucial. If people don't read how much of the dunk to use, they could easily exceed the safe dosage for tadpoles.

Angela Chen, just ran across a great page about algae control while researching water gardens: https://aquanooga.com/how-to-control-pond-algae/ 

HU-477055775, Some tadpoles, those such as bullfrogs, may take as long as two years to develop into frogs, but six to 12 weeks is the common length of time for most kinds of tadpoles to become frogs.

https://www.google.com/amp/s/theconversation.com/amp/are-mosquito-killing-natural-pesticides-unintentionally-harming-frogs-175194

Considering frogs and toads very much like mosquitos and mosquito larvae as a food source, what most likely happened in Kathy Durrum's situtaion is that by introducing mosquito dunks and killing the larvae they removed the food source for the frogs which caused a large number of them to starve to death. Removing the dunks allowed the mosquito population to proliferate which then also allowed the predators of mosquitos, frogs and toads, to also proliferate. Any time you remove or reduce the amount of an animal from an environment that is a small ecosystem you're doing damage to that entire system, not just the one specific animal in it.

It's 2026 and I'm still using Mosquito Dunks in my 6 ponds, 5 in ground, one container. All of my ponds have native Pacific Chorus treefrogs and their tadpoles, dragonflies and other aquatic life. (I don't currently have any fish, when I did I still used Dunks) My first lined pond was built in 1997 and the other 4 in 2004. My cats, squirrels, opossums, raccoons, tons of birds and likely neighborhood coyotes have all drank out of my ponds for all these years. I have never seen any adverse effects.