Sad news...my daughter excitedly woke me up this AM to feed Camperboy. When I turned on the light, I spotted him quickly laying on his back in the back corner. Fortunately, she thought he was sleeping. Any ideas on what might have gone wrong? I did a partial water change (2.5 gals) yesterday after introducing him to the tank on Thursday. Could that have been a bad move? The rest of the fish are quite lively. Now that there's been a death, do I owe them another water change? RIP Camperboy.