Hi guys I've literally just joined this site a few minutes ago and I'm not overly sure how it works so if I've posted this in the wrong place I apologise in advance. I got my first 25litre tank 6 weeks ago with a few live plants I got given from a friend. With the advice of an experienced friend I got my tank set up with a filter and heater and got it cycling for 10 or so days and tested it before I purchased a beautiful red dragon betta. The betta was fine for 2 weeks, seemed extremely happy and healthy so I then added in 2 amano shrimp which both settled in perfectly with the Betta. 6 days ago I was in my local fish store and with the advice of one of the workers he said a school of neon tetras would go fine with the betta so I purchased them. A day or so passed before I noticed the neon tetras were absolutely covered in white spot, and my betta had a few so I went out and bought white spot treatment and followed the instructions on the bottle. Since then the neons seem to be fully cured and I have moved them to my friends tank as I think they were stressing the betta out really bad. Unfortunately I came home today to find my betta has passed away and I am a lot more heartbroken than I thought I would be. Now I just have my two Amano shrimp and I don't really know what to do from here. I want to get another betta and keep him by himself this time because I don't want to have to go through this again. Should I do a 100% water change and start fresh? Any advice is appreciated. Sorry if I seem like a newbie, it's cus I am!!