My fish need help!
At least one of the goldfish in the pond has what looks like ulcers on both of it's sides (going by various pictures that I found online). Most of what I've read online says that this is propably caused by some type of bad bacteria but I can't seem to find what the best way to treat the pond is to make sure that none of the other fish, particulary my koi, develope problems. Will it help if I do a partial water change? Currently the water is the clearest that it's been in well over a year which I've attributed to the large amount of parrots feather growing in the pond. I haven't added in any new fish in the last couple months. The pond is about 5 feet wide by 11 feet long and ranges from 2 to 2.5 feet deep. I know that there is a bit of muck on the bottom of the pond that I need to clean out but I don't know if that is contributing to the problem. There is no way I'll be able to get all of the fish out of the pond to treat them so I need to be able to just treat the whole pond.
Can anyone give me some advice as to what to do?