What you are talking about is called ‘dumping’ of feeds and it should not be done.
The dumped fish feeds on the pond sides have a great potential of attracting predators such as birds that may predate on the fish but also pass on parasites and diseases to the fish.
Parasites such as helminths are known to be in all vertebrates and birds could be secondary hosts of these parasites.
Feeds dumped into the pond waters and remain uneaten have great potential on depriving water quality parameters; things like oxygen, and PH will change, this is because the uneaten feeds are now considered as waste feeds that may require some microbial process for them to be broken down and the whole microbial process is oxygen consuming.
A farmer should also be aware that the dumping of feeds could lead to diseases. Disease such as brown blood /nitrite poisoning is caused by the presence of excess nitrites in the culture system water.
It should be noted that nitrites originate from ammonia whereby ammonia is also produced from the “dumped” protein-containing feeds.
Brown blood disease is characterized by brown gill tissues instead of the reddish/pinkish colour known and also brown blood in fish.
Environmental gill disease could also be a result of irritants such as suspended organic solids that cause gill inflammation.