I bought four Black Harlequin Rasboras a week to two weeks ago for my nieces' tank. Last week, one had been acting strange and was keeping itself apart from the rest by hiding in the plants and even going after the other rasboras. It died that night. Fast forward about three days later, I guess, and a second one died but everybody was acting fine. No odd behaviors were observed. I put it down to the usual fish death, which I had assumed since the LFS I got them from did not have a guarantee or a return policy for them. Fast forward to today. This morning when I woke up, both of the rasboras that were left were schooling together and moving around like usual. Then when I was gone for a few hours, one of them died. I came back to this - image This happened in a matter of HOURS. What in the heck is going on? The Cardinals, Neons, baby Platy, Betta, and RCS are all unaffected.