Fish from the North Sea are only edible fish, aren't they?
Strange! For us it has become a matter of course to import aquarium animals from all over the world. Although, on the other hand, we have two seas, the North Sea and the Baltic Sea, right on our doorstep, from which we could also generate numerous interesting fish for the home aquarium. One of them, the common dragonet Callionymus lyra, was one of the first fish ever kept in an aquarium in Europe in the 19th century. Certainly, the keeping temperature plays a very important role for many animals from the North Sea, but some interesting species can already be kept in a cold cellar or an unheated room. It is sad, that all those who are very seriously involved in the hobby of vivaristics, often have to move in legal grey areas, and that some animal protection associations and politicians would actually prefer to ban our hobby completely. However, this would not only harm the pet trade, but it would also benefit many illegal animal traders who could now charge astronomical prices; not to mention the damage to the smuggled species. Furthermore, our population would become even more alienated and detached from nature and the environment, so that ultimately no awareness of living creatures and ecological interrelationships can be expected any more. Whether this is good for our only secondarily existing and rudimentary nature can be highly doubted. Obviously, private vivarists are not allowed to do anything, while industrial users and corporations are allowed to do all kinds of things. Is such schizophrenia acceptable? (It is really crazy: Someone who catches a few of the tens of millions of gobies living here for his home aquarium in the so-called "Wadden Sea National Park" during his holiday commits at least one offence, while on the other hand no one crows when commercial fishing simply throws away millions of tonnes of unwanted fish). Something is going wrong... But it is precisely vivaristics that gives animals a much higher value than fishing ever can. There are even scientific studies on this - albeit with regard to tropical animals. In relation to its body weight, an "aquarium fish" caught in the sea achieves at least ten times as much added value in the course of the trade chain as a fish caught only for the frying pan. It always makes me very sad and angry, that politicians obviously don't want to see such connections. Instead, they only think about further criminalising private animal owners. That is why I would advise anyone who wants to get seriously involved in vivaristics or aquaristics to join an association that is affiliated to the VDA, if possible. See also: VDA-Online.de.
General information on keeping and caring for North Sea animals
Keeping North Sea animals is basically possible, if you are able to meet the space requirements of the individual species. It should be clear from the outset that many species can grow exorbitantly large and require appropriate housing in order to be able to care for them in a species-appropriate manner on a permanent basis. It may be that, for example, a common lobster Homarus gammarus, which weighs about 600 grams, can be kept in an aquarium with a tank length of only 1.20 metres and a depth of 50 cm, but since such an animal grows considerably larger over the years, it is important to consider early on whether it would be better to offer it a tank with a tank length of 1.50 to 2 metres and a depth of considerably more than 70 cm. Also, cold-water species in particular often live to a very old age, so that some animals can even outlive their keepers! Cylinder-anemones in aquaria, for example, can reach an age of 80 years and more. It is also very important to think carefully about the socialisation of different organisms in an aquarium from the outset, as almost all North Sea animals are pronounced predators that basically eat everything that is smaller than themselves, or that cannot avoid them in the confines of an aquarium. Compared to the sea, an aquarium - no matter how big it is - is a rather small space in which the animals cannot permanently avoid each other. The courtship behaviour of some animals also means that the tank is simply too small for several individuals of a species during their mating season. An example of this would be the common dragonet Callionymus lyra. If too many males are kept in an aquarium that is too small, the inferior animals will jump out of the tank as soon as they have discovered an opportunity to do so. In addition, care must be taken to ensure that the temperature of the tank does not exceed the 18° Celsius mark if possible, and that the animals can overwinter in temperatures that are as cold as possible. This can best be achieved in an unheated cellar room where, with a bit of luck, you can create a natural fluctuation range of 4-18° Celsius. In the meantime, I have perfected this procedure somewhat, as in the warm season I can permanently cool down my cellar with the North Sea aquaria to 16° Celsius using a mono-cooling block. In the process, the block draws in the room air of the basement and blows the cooled air back into the room, while pumping the warm exhaust air out through the basement window. I copied this cooling technique during the summer from the Multimar-Wattforum in Tönning, where the waste heat from aquaria-cooling is used to heat the visitor`s area in front of the tanks. If the air-conditioning of the room is right, the panes of the aquariums do not mist up. However, if the gradient between room temperature, ventilation intensity and aquarium temperature is too great, the only way to prevent panes from fogging up due to condensation is, to install a pane heater. This method was used, for example, in the temperated aquaria of the Lower Saxony State Museum. Most books demand, that North Sea animals should be kept permanently at temperatures between 12° and 15°. However, this does not correspond to natural conditions, because of the lack of a cold phase in winter. If the water is cooled down to temperatures of 4 - 7° Celsius in winter, you can see from the behaviour and colours of the animals, that this cooling does them a lot of good. Many animals also need this cold for gonadal maturation in order to become able to reproduce. Some animals, such as the eel pout Zoarces viviparus, reproduce exclusively in winter at Arctic temperatures. Other animals, such as the sand goby Pomatoschistus minutus, are also suitable for keeping in small aquaria. Such animals are ideal, because they come from intertidal areas where they are exposed to great extremes such as fluctuating salinity, as well as heat and cold, and many predators. Some species, such as seahorses and pipefish, only accept live food or are food specialists. So it is better not to keep them, if you cannot obtain the food in sufficient quantities. Feeding filter feeders such as mussels and sponges can be similarly problematic. It would go beyond the scope of this website to list the detailed care requirements for each species, so I have limited myself here to these general tips. However, I have included some care instructions in the text for some of the species I have introduced, so that you can learn some basic things here. If you are interested in the operation of saltwater aquaria and the associated technical equipment, you should consult the relevant specialist literature or the appropriate forums. However, I would like to point out, that there are also new developments, trends and fashions in this form of aquaristics, which newcomers may not immediately recognise as such. Therefore, I would always advise you, to seek contact with other marine aquarists or institutions, that already have several years of experience in this field, before you start your own saltwater aquarium. This can save you many failures and wrong acquisitions.