Abandoned fish Koi

Someone must have dumped a few fish in it that went on to reproduce. They look like large gold fish, 6 plus. I spoke with the community president and he has no idea how they got there but they are a recent development. Are there steps we should be taking so they have a chance to survive or is this a doomed situation? I dont think the housing association is going to approve any measures that involve expensive upkeep.

This happens all the time unfortunately. Being such a large pond, doing nothing will allow the fish to survive, though theyll reach a point where theres more fish than food and start dying off. If you of someone were to remove them, theyd probably survive as well, but just not in your communitys pond. I say just let them be and let nature take its course.