So I have a 29 bowfront with 10 harlequins and 6 rummy nose (used to be 10). I found 4 dead today, a couple hidden in plants and obviously dead for a day or two. But no odd signs, no ich, no bloating, just dead, and the other rummy's aren't super red on the nose..I do water changes every other day and the harlequins are a-okay. I recently put in cuttlebone for my 4 nerites but that couldn't be the cause right? What's going on?