First loss....

[reefgirl189]

While we are kind of on topic would you replace that fish without knowing the reason for its death in the first place?

The reason I ask is because my sailfin passed away about a month ago and I have no idea why. I really miss him and I want to get another but I'm afraid he'd meet the same demise. So is it irresponsible to get a replacement fish without knowing the cause of the death on the first one?