I had an unexpected death today. This is the first such death that I have had in an extremely long time in the marine hobby.
Two weeks ago today I purchased a Porcupine Puffer and a Dragon Wrasse. Both were added to my 38 gallon quarantine aquarium. Both fish, by all visible signs, were extremely healthy. In addition to physical appearance, their behavior was perfect. They were both swimming around, eating aggressively, and even approaching the front glass "begging" for food.
Today I go to feed the fish and the Dragon Wrasse is dead. The Porcupine Puffer is happy, visually perfect, and ready to feed. I test for pH, ammonia, nitrite, nitrate, alkalinity, calcium, salinity, and temperature. All levels are within the range I want. At face value there is no explanation for this situation.
This, however, is what we learn about marine fish as we develop experience in this hobby. Often times there is not an explanation for an unexpected fish death. These fish are collected from the ocean in a net, brought to the surface with little acclimation period, thrown in a cooler, taken to a holding facility, shipped to a wholesaler, flown by air to a distributor, and then transported to a LFS. At the LFS they are usually acclimated improperly, and then placed on display in bright lights with little to no places to hide.
All of this occurs over a very quick time frame, often less than 1 week, and the first opportunity for recovery the fish has is when we bring it home. This is why a quarantine is so important. Fish need to time to rebuild their immunities and regain their strength before being placed into a captive environment with fish that have established territories. Fish need the quarantine period to get used to the feeding schedule and offerings.
I could speculate all day about what caused this death. Internal parasites? Damage to organs during collection? Cyanide? It is impossible to say. But the cause of death is not important. What is important is that I gave the fish the best possible chance for survival, and that I protected the livestock in my display from possible infection.
If you don't have a quarantine, let this be your call to action. You simply can not attempt this hobby with one.