As far as the pond is concerned, this month does not differ very much from the month of July. Also during this month water temperatures can be relatively high. So, remember the oxygen content and apply a aeration pump, if necessary.
Thin out oxygen plants and remove finished flowers and brown leaves of water lilies and marsh plants. Special tools, f.e. the Pond cutter & Pond pincers can come in useful here.
Check whether the pond filter still has a sufficient amount of water. If necessary, you should rinse or replace the filter material. To obtain crystal clear pond water you are advised to use good quality of filter carbon. Using this carbon, you can even remove colorings and phenols from the pond water.
Fish will grow well now. Their range of coloring is developing and their condition for the coming winter months is being built up. Therefore feed your fish liberally. However, you should take care that no feed is lost. Young herons will have fledged and have to look for their own feed now. They are active especially early in the morning and during twilight. Therefore protect your pond fish.