Many years ago, when I was fairly new at the marine hobby, I was really overcome with excitement. I had a fish only system at the time, the move to a captive reef was yet to come.
So what was all the excitement about? I had seen and ordered to be kept for me a juvenile emperor angel (Pomacanthus imperator). This 3″ or so beauty was cruising up and down the dealer’s show tank, looked in full health, and could not be resisted. I did some research in the dealer’s shop using a book that he provided. It was fully compatible with my aquarium stock and the aquarium was quite large enough.
The juvenile emperor has a blue body with a series of white rings and is most definitely beautiful. This colouring is lost as the fish ages and it turns into beautiful nearly horizontal narrow yellow stripes interspaced with blue. The top of the fish’s body is yellow and the bottom dark blue, with a yellow tail. Perhaps the most striking is the white mouth area, with the eyes covered in dark blue – this gives the fish a very ’cool dude’ appearance. The full adult size is about 12”. Why there is this colour difference between juvenile and adult is open to speculation. It has been said that perhaps the juvenile colouring protects the fish from the attention of the territorial adults.
Anyway, an aquarium that had contained two clowns was prepared so it could act as a quarantine tank. The fish was carefully introduced to this temporary accommodation and the lights left off. In a day it was noticed to be eating some red algae that was growing on the rocks. A small amount of flake was offered which the fish took without problem. The fish fed from day two without problem, on any fishy food offered, including blanched lettuce.
After two weeks the fish was transferred to the main display aquarium. There wasn’t any problem at all, the fish swam out of the bowl it had been transferred in and cruised regally up and down its new home. All areas of the aquarium were checked by the fish and it was completely settled. The other fish had no real interest in the newcomer apart from a little caution, probably because of the newcomer’s size (the other inhabitants were smaller).
The fish lived for many months quite happily. It fed well, rising with the other fish to the fingers. Dietary needs were met.
One day, oh, I remember it so well, I went to the aquarium to see the fish and in particular my ’special’, and it was very slowly moving along the bottom of the aquarium. The other fish were fine. I put my hand near the glass and the fish did not respond, though the others did. Hoping there wasn’t anything wrong, I waited. I couldn’t see anything wrong with the fish itself.
The fish didn’t improve. Water testing followed, there was nothing wrong. By this time the fish was laying upright against the front corner of the aquarium, not swimming at all. Breathing was quite slow and as it had always been. I looked at the fish closely but could see nothing wrong. There were no torn fins, damaged areas of the body, or cloudy eyes. I got a magnifying glass and looked closely at the fish, but couldn’t see any of those dreaded tell-tale signs of marine velvet or white spot. The fish did not improve.
Clutching at straws, I did a water change with carefully matched SG and temperature. I then dosed the tank very carefully with a copper medication. Though this is effective for some problems, no medications should be given for the sake of it. The copper dose was maintained carefully and none of the fish showed any stress, including the emperor which did not improve. The other fish were eating, but not the emperor.
After a few days (I didn’t record the exact number, it was around 7 to 10) activated carbon was added to clear the copper, followed by another water change. The emperor had moved a little, it was now leaning against the middle of the viewing glass.
I don’t know why, but I had the sinking feeling that the next day the emperor would be gone. I remember that feeling! The next morning I went to the tank and the emperor was still in the same position. It was dead.
I felt guilty for quite a long time, and no-one I spoke to could give me any clue as to why the loss had occurred.
Thinking about it later, and even now, I think that I acted reasonably in the circumstances. As there wasn’t a clue to be seen on the fish of the cause of the problem, I have wondered if it was internal, a parasite perhaps. I will never know.
I cannot keep an emperor now, as first my current aquarium is too small and second the fish is not reef compatible. If I could, I’m sure an emperor would be among my livestock.