Fish Loss And Replacement

The reef aquarium looks beautiful, walking by it always attracts the eye. The aquarist is so pleased, everything that was said about research and patience was worth it. The inner aquarium world is settled, healthy and vibrant.

It has been said by me before that the aquarist is really an employee, not of the life in the aquarium so much, though it sometimes seems that way, but of Mother Nature. It’s she who really decides everything based on the conditions within the aquarium so maintaining a healthy aquarium environment is obviously worthwhile. But there is one event that is not always based on conditions, it just occurs and this is death. One day a fish is there and apparently happy and healthy and the next nowhere to be seen.

The aquarist completes a feed and hopes the fish will appear, but no, it never does. How has this happened?

To be truthful who knows but there are possibilities. When the fish was purchased what age was it? – simple answer, we don’t know. Perhaps it had come to the end of its natural days, hastened maybe by the stress of capture and transport. Disease can be ruled out generally if the fish has been present for a long time. If the fish was a recent or more so a very recent addition then checks need to be made on the other fish (a general ongoing check should be routinely made anyway, an easy time for this is at feeding). Are there any signs of disease, any little white spots on the skin or fins, any changes in breathing, any changes in general behaviour? Hopefully not. Some disease problems require treatment by copper and in a reef system this is impossible as copper will have a very detrimental effect on corals. The best way is to treat new fish at the other end – immediately after purchase – by placing them in a quarantine tank for at least two weeks preferably four. This permits the aquarist to easily watch for signs of disease and if anything appears it can be much more easily treated. This goes a long way in avoiding the horrible problematic question of disease in a reef system. To jump back a bit, fish should be carefully studied at the shop for signs of problems in the first place, nothing should be taken for granted.

Anyway, what about the missing fish? Few aquarists will be willing to wreck the reef in a search for it. Unless the location of the fish is obvious and it can be reasonably easily removed, the best way is to leave the fish and increase the seawater quality checks particularly if the fish was a large one. The fish will follow the route of all dead things and disintegrate naturally and in a reef environment probably feed tiny reef inhabitants in the process. Normal partial seawater changes should continue unless there is a need for a temporary increase because of, say, nitrate. The aquarist following a loss procedure will reinforce confidence in the ongoing health of the aquarium.

Right, so the period following the fish loss hasn’t indicated any problem. Is the fish to be replaced? The normal answer to this is yes, but if the fish load was at maximum or a little over then that other word, discipline, arises. Take the opportunity to accept a reduction in fish load and reinforce the sea quality equation. If there isn’t a question of overload or close to it then other considerations arise. Are the remaining fish peacable, a little aggressive or just aggressive. The new fish will not be a member of the club so will need to be able to withstand the actions of the current inhabitants. Also, in the other direction, the new addition should not be likely to give trouble to the current inhabitants by being too aggressive. Also in addition, the final size of the new fish needs to be considered, first so that the fish load doesn’t become excessive causing seawater quality loss and second so the fish can find a place to go at night in order to avoid stress. Many of the caves and crevices might well be occupied by the current fish who will not take kindly to a takeover bid. The procedures for fish replacement are much the same as those for initial stocking except that the new fish is joining the existing club.

While on the sad subject of fish loss the occasion can arise where a fish has not hidden away but is obviously struggling, unable to swim properly, floundering about or possibly laying on the sand or floating at the surface. Faced with this the aquarist sees the obvious – there is nothing to be done for the fish. Should it be left? Or should the aquarist end the misery? Having accepted there is nothing that can be done the aquarist can quickly place the fish in a small bag. Then having quickly twisted closed the top of the bag, the bag can be swung very hard against a solid surface, say a brick wall, a rock etc. This will end the misery of the fish and that of the aquarist.

If the aquarium has been carefully set up in the first place and if proper attention has been given to livestock selection, plus ongoing maintenance is done properly the potential for problems is much diminished. Fish might die as all life eventually must. However, the major part of the aquarium’s life will be as desired: colourful, vibrant, fascinating, educational and stress reducing.