Yes and no. That's actually part of what's researched before they do a treatment. From what I know, it takes about a week from deciding to "treat" a body of water to actually treating it, at the fastest. They collect a bunch of samples of the body of water, find out what's considered norm from past samples, what's going on now and find a method of approach and the weakest concentration needed.

Frogs and some fish feed mostly on the larva stage of their lives (egg>larva>pupa>adult). The hormone treatment they use, can't remember it for the life of me, affects their pupa to adult life cycle. Something about screwing up the deterioration of the "shell" before they turn into adults. It stays hard and they are essentially buried alive since the hormone responsible to degrade the shell, so they can emerge, doesn't function properly. But that hormone, in the past 20 years, has not shown to affect fish, frogs or mammals, even down the food chain. There's technically 2 hormones, if I remember right. It was 2 years ago when I was hired to do a research project on prediction of mosquito migration and outbreak spread. My memory is not 100% on this. But one hormone is better to attack than the other because it doesn't affect anything other than mosquitoes. Obviously, "so far known". But it's also been a few decades since testing this at a pretty good scale. Only problem with this method, you only have a few day window of applying this in their life cycle. That's why consistent testing is done and it's used proactively, rather than reactively.

But some of the other tactics, is to speed up and help the flooding/draining process that happens naturally. There are waterworks programs that route water and keep it moving enough to deter mosquitoes, but not affect other wildlife (fish, frogs, other insects, fauna, etc). Those are technically the most effective, economical, and least likely to cause wide scale harm if a problem occurs. Plus, there's specific planting of native plants that suck up water fast. Then there's educating the public to not be retarded about standing water. Plus a few other minor methods. Mosquito control is not a one vector approach. The idea of "one action to rid them all" was shit canned long ago. Literally. The guide for mosquito control, that county commissioners and other gov officials here have to read, specifically mention that there is no single approach to mosquito control and no one should ever think there is one. It's been multi-faceted for many decades. At least in Florida. Other states, apparently, have not adopted that approach.

Edit: Shit, failed to explain my yes/no response. By yes, other animals can potentially be affected. But there is a conscious effort to use minimal concentrations of chemicals needed. Also, they don't intend to eradicate all mosquitoes. If the population of larva and pupa found in a body is deemed normal or below normal. No treatment is done. That way there's enough pollinators and food for the local wildlife. Also, if there isn't an outbreak too. When there's cause of concern for some disease that's actively being found, it's open season for mosquitoes until the outbreak is considered over. It's a really rough balancing act. It succeeds often, but you only hear about the few times it fails. Out of all the research, reports and interviews I've done with folks, it's a conscious balancing act and continual learning process with those in the field. But to be fair too, I only talked to professors who are active in research, CDC and officials in counties that matter. I honestly don't know what it's like in the hillbilly Florida counties. They probably still think bathing makes you sick.