What wonders our reef or fish only aquariums are. There can be no argument that they are a thing of beauty, with inhabitants created by nature. To sit and watch a marine aquarium is to enjoy calm. Diving or snorkelling on the wild reef is very similar on a large scale. Nature is showing off, anything I can do you can’t do better. Colourful fish in swarms against a blue background and under a rippling silver sky. Corals in many colours, some swaying to the music of the sea. What an idyllic scene.
Let’s spoil the picture for a moment. It is a large and wonderful creation, a wild reef. As divers know, there are dangers for the unwary. Ever been snorkelling and got a bit too close to hard corals on the reef crest? Ever been pushed against the corals by wave action? Uncomfortable is the least descriptive way of describing it. Ever touched a fire coral (Millepora sp) by mistake? Not to be done twice, that’s definite. A wary eye has to be kept for danger, both in the accidental touch and in fish. Great barracuda (Sphyraeua barracuda) have a fearsome reputation. Divers are careful, even though the reputation is probably exaggerated, as in the case of most sharks. The reef is a constant battlefield, where corals wage war for territory, and mobile life such as fish are constantly hunting for food and attempting to avoid becoming it.
So our marine aquariums are stocked from the reefs, for the most part. We are all aware that care has to be taken with stocking to avoid one fish being food for another, or fish fighting, or some coral being eaten by a butterfly fish. I believe that aquarists are very successful at avoiding this kind of problem.
We are also aware of the dangers of some fish. For example, the lion fish (Pterois volitans). It is a lovely and unusual fish with superb finnage, but be careless and be pricked by a spine – venom will be released – and you’ll know it! Similarly the yellow fox face (Lo vulpinus). Not as dangerous, but dangerous enough. When I kept one of these, my wife kindly acted as a shepherd with a wooden ruler to hand in case the fish came too close. There are quite a few potentially dangerous fish, or very dangerous fish, that can be kept by the home saltwater aquarist. “Know the fish” is the safest line, find out all there is on the internet and in reference books.
The same applies to corals. Some corals are so pretty, so colourful, or just so innocuous in appearance, that the thought of danger just doesn’t arise. The result of touching a fire coral has already been mentioned. A carelessly withdrawn arm from a hard coral aquarium reef can easily result in a cut. Putting a hand in the aquarium with an existing cut can be hazardous. Have you ever seen aquarium water under a powerful microscope? It’s a world in itself. Of course, we are used to the attacks of virus and bacteria, and have defences against them. However, they are land or air based. What defence have we against saltwater based micro monsters? Care is the answer.
Talking earlier of innocuous corals brings me to a purchase that many aquarists make, including myself. This is the very available common button polyp (Palythoa and Protopalythoa sp). They look like a mass of small daisies, each one touching its neighbours. These button polyps are often obtained on a piece of rock (another bit of live rock for the system) and often covered overall. They are a very good addition to the reef aquarium, as they are hardy, generally undemanding, and do not require particularly powerful lighting. They are quite likely to spread, a pleasing prospect. They enhance the aquarium reef by adding to the overall reef diversity in colour, in shape, and in placement (they can normally be placed quite low down in the aquarium).So why are these little ‘daisies’ included in this text?
The mucus on these dainty little polyps contains a potent palytoxin. It is so potent that certain tribes that lived in the Pacific area would dip their spears and arrows in the toxin to paralyze their enemies and wild food animals*. As already mentioned, the aquarist with existing cuts on hands or arms should take care anyway, this is a reason to take particular care. Even if there are no cuts, be careful when handling button polyps. Wash the hands thoroughly when finished.
Some dangers should not, in my opinion, even be on sale, but should be left in their wild home. For example, the blue ring octopus (Hapalochlaena maculosa). This is very attractive and grows to about 12 cm (circa 4″). However, a bite from the octopus and it is going to be realized why they are so dangerous – the bite can be life threatening. Another example – the stonefish (Synanceia varicosa). This is not an attractive fish at all, and is sedentary by habit. It has spines like hyperdermic needles that can pierce a softer soled shoe. The pain is said to be beyond belief, and very urgent medical action is needed to avoid severe problems, or even death. The only reason I can see for any aquarist wishing to keep a specimen is because it is so dangerous, a sort of ‘macho’ thing. Leave them and others of their species and similar species in the sea for which they are well designed.
It is seldom that we hear of a severe problem caused by livestock. Perhaps this is because of knowledgeable aquarists, or, perhaps more likely, that they are very infrequent. The aquarist should, however, be aware, and enjoy his/her aquarium, and not be endangered by it.
(*Source: Aquarium Corals, Eric H. Borneman)