I bought 2 5" a few days ago, I have them in a 75 gallon tank until they are ready to take on my 210, 2 hours ago they were just fine and when I went to go to bed the one was wrapped around the filter, as I scooted him off he look like he had been nipped and started to nose dive twirl to the bottom of the tank, they are tank mated with 9 1" tinfoil barbs... what would have caused this? Did the one nip at the other and kill it?