Hey everyone. One of my betas died early today. I am wondering, since I don't know cause of death what I should do to ensure that the others don't die as well. At the end of his life he was very lethargic (but me being a new owner, I thought this was his personality). Anyhow, then he ended up swimming with his body vertically when he swam. Then he couldn't stop flipping upside down, After the upside down thing, he died about 30 minutes later.
Any advice on what he may have died from, and what I need to do about the others?
I didn't notice any injuries or spots or white cottony stuff.