I have recently faced a problem in my lucky bamboo. I bought them about a year ago. There were no problem during past year. but in the past two weeks I see some parts on the stems colored in red to brown and two leaves declined.(I attached the photos) The only changes in caring bamboos in recent weeks was changing water since I read an article suggesting changing water every two weeks to prevent rottened roots.(I had not changed water since last year but there was no problem). another one was adding few drops of fertilizer to the water.
Could you please tell me what is happening to my plant?