You can sort of think of H. azteca having a similar role in your pond as springtails in the substrate of a terrarium. They won't do any harm, only consume detritus, algae, diatoms, etc. They are not toxic for your pets to consume, just normal decomposer fauna in aquatic environments. They are cosmopolitan, important nutrient cyclers and food sources for primary consumers: small invertebrates, fish, birds, etc in nature.