Hi Steven! That’s fantastic that you’re planning to donate to cost-effective animal charities. Thanks for thinking of ACE’s Recommended Charities and engaging with our work. When people ask us about the most impactful animal charities to donate to, we typically recommend donating to our Recommended Charity Fund. Our team of researchers decides how best to allocate this money among our Recommended Charities based on their current funding needs and the latest information on which activities this money would fund so that we can be confident that donations are being used as cost-effectively as possible. That said, here are some things we think are worth considering if you prefer to select charities yourself:

• At ACE, we agree with the other commenters regarding the importance of wild animal welfare, given the sheer number of animals living in the wild, the likelihood that many of these animals suffer intensely, and the fact that the wild animal welfare field is currently so neglected. It’s great that you’re planning to look into this in more detail. If you haven’t seen them already, some helpful resources include this EA Forum post and a recent 80,000 Hours interview with Cameron Meyer Shorb (head of Wild Animal Initiative). ACE’s Why Wild Animals? page also cites some useful sources.
• As for fishes, there is strong and growing evidence for their sentience and capacity for pain and pleasure. This briefing gives a helpful overview; you could also check out this EA Forum post or this recent interview with Doug Waley on the How I Learned to Love Shrimp podcast.
• While there’s little current evidence for shrimp sentience, this is because there has been very little research in general rather than because people have found evidence against shrimp sentience. Shrimp Welfare Project has published an overview of the existing evidence, and this report by Rethink Priorities gives a great rundown of the potential welfare threats of shrimp farming. When you consider these threats, the huge numbers farmed, and the reasonable probability of shrimp sentience, it seems likely that current shrimp farming practices could be a major source of suffering.
• Finally, while the kinds of work done by Faunalytics and New Roots Institute are less direct than some of our other charities, we think they’re likely to relieve a great deal of suffering by empowering other advocates and organizations to help many more animals than they otherwise would. Effective animal advocacy strategies to build a world where animals experience well-being has a relatively long time horizon. We expect that the work these organizations do speeds up the timeline significantly. The faster we can bring about a future where animals are protected, the more suffering is abated. 

Hope that’s helpful and wherever you end up donating, thank you for thoughtfully trying to create a better world for animals!

- Max

Hey Steven, I think it's great that you are looking into animal charities and it looks like you have done some good initial research here :) 

There are a couple of points that I imagine many people would want to challenge, especially around invertebrate and wild animal welfare. If you don't mind writing it out, I imagine your thoughts on factoring in uncertainty in your decision-making (i.e., on low-probability, enormous impact scenarios such as in invertebrate welfare) and your thoughts on aggregating welfare among individuals (i.e., on scenarios where orders of magnitudes more animals are affected, but each to a smaller degree such as in invertebrate welfare and in wild animal welfare) would provide a good base for these discussions to happen.

I think these are important discussions in this context specifically, because if you take neglected animals such as invertebrates and wild animals into account, you may want to explore the EA Animal Welfare Fund or ACE's Movement Grant instead of or in addition to ACE's Recommended Charities. I also want to flag that Faunalytics' research shouldn't really be boiled down to "statistics", but I imagine your stance on New Roots Institute (i.e., helping animals directly > education/one-step-removed?) applies here too. 

All of that being said, based on your expressed views, I think you will find Sinergia Animal to demonstrate the best numbers yet. 

Lastly, you may find this perspective from ACE worth engaging with, specifically their perspective on ranking charities within recommended charities:

"Update the decision-making process so that it directly compares all recommended charities on marginal cost-effectiveness. Our basis for deciding whether to add a Recommended Charity is whether we think it would lead to more animals being helped on the margin (compared to having a smaller number of Recommended Charities), which is conceptually different from ranking charities. Given the types of uncertainty currently faced by the animal advocacy movement when it comes to calculating cost-effectiveness, we decide whether a charity should be recommended based on a range of decision criteria rather than scoring and ranking charities based on our sense of their relative marginal cost-effectiveness. In the future, if we had sufficiently robust evidence to form reliable cost-effectiveness estimates, including evidence or good proxies for speculative work with complex long-term theories of change, it’s possible we would move more toward the kind of ranking approach that GWWC suggests. Additionally, we consider relative cost-effectiveness during each Recommended Charity Fund distribution, where we adjust the size of each grant depending on the most up-to-date plans that charities share with us." [emphasis added]