Top article ...... growth of our "jumbos" Factors limiting the growth of ornamental fish Author: Wilson Bruno Vianna and Isaiah (11/09/2010) aquaflux.br/conteudo/artigos/fatores-limitantes-do-crescimento-dos-peixes-ornamentais.php One problem we often face when choosing fish to populate the aquarium is the size that the animals can reach. When it comes to small characins, barbs or even some medium and some large cichlids, the maximum size is not a problem, since these fish reach standard size, making it easy to scale the tank that will house them. When it comes to aquarium called "jumbo" the picture changes. Exotic fish as some primitive (gars and Bichirs) as well as some old acquaintances such as pangassius the aquarium, arowana pacu and appear in literature as fish that reach large in nature, but as in aquaria? It is common to see in some chips Fish the Net actual size, nature, and a reduced size in captivity. But what actually happens? The farmed fish in aquarium, depending on the species, may alter its original size so significantly? This change is always caused by improper treatment or aquarium can limit growth having good living conditions to the animal, well fed and well with parameters similar to the original habitat? Often see in forums dedicated to fishkeeping doubt beginners and even more experienced aquarists about the matter, and often the answer is vague, based on factors such as atrophy from lack of space or just cndições inadequate. But what is unhealthy condition. A fish that normally lives in environments of millions of liters of free nitrogenous compounds certainly not be in "proper condition" even in a tank of 3000 liters or more. In our aquariums, no maintenance is done, the temperature and the parameters will never be equal to the natural habitat ... our effort, so it is always in order to provide the best possible environment, even the best is always below the original. But then why do we see fish five or ten years of age in captivity with sizes well below the maximum prescribed? If longevity and health were apparently not affected, what was the reason for the lack of growth? Hormonal factors, lighting and absence of nitrate concentration in the water found in nature are crucial to the optimal development of the species? In this respect the material on the Net is very scarce, getting the opinion of the aquarist usually directed exclusively to their personal experiences, ie, observing, for example, a spotted gar (Lepisosteus oculatus) for several years, fed with live fish and a tank absolutely compatible, yet the animal was barely above 0.50 m. well below average placed in the specialized literature (0.80 m. 1,20) unless the animal was collected in nature having already reached the maximum size species. We asked the opinion of Professor Wilson Vianna, biologist, creator and aquarist to try to analyze all the points that may influence a healthy growth of ornamental fish. Bruno Isaiah As always, the topics under discussion AQUAFLUX puts exceptionally delicate subject of doubt among the whole community ornamental aquaculture. I thank colleagues moderators the opportunity to express my humble opinion. I believe that no conditioning that offer our fish will be better than the one they have in nature. To begin the study of this sensitive issue multiple items should be examined to reach a conclusion acceptable: FOOD / NUTRITION Often make the mistake of feeding the super our belief that more fish food bring more they will grow, however, recent studies have revealed that most ornamental fish can not metabolize more than 36% protein. Thus, we can deduce that a feeding with high protein values require the production of a large amount of energy, as well as a large production of enzymes digestórias. The excess, the animal does not metabolize, is excreted almost in natura, even leading part digestórias enzymes produced in the process. This product, in contact with water, will rise to the famous "nitrogen" (nitrite, nitrate and ammonia) harmful to the health of fish and inhibiting their growth. QUALITY AND QUANTITY OF WATER I often say in the courses I teach that there are four important factors in creating ornamental fish: water, water, water and others. By way of illustration it is worth mentioning some interesting cases: 1 - The friend and dedicated creator of Discs Roberto Romao has several aquariums, at his residence, one of which has an input and an output of water, where the gradual change occurs 24 hours a day. Aquarium fish that are exceptional, do not get sick and grow very, reaching twice the size of the disks of other aquariums. Out TPA constant all other parameters are identical to other aquariums. 2 - I create Symphysodon flags albino in my lab. When they are a month old puppies are taken to the fish and placed in tanks of 4.500 liters where they complete their development to the point of sale. As a safety margin woodblocks are kept in aquariums, in my lab. These matrices can never reach the size of those that remain in the tanks with more water. 3 - A few years ago I was in Manaus and visited some wholesalers of ornamental fish and I observed some discs - native - created and collected in the wild - HUGE - sizes never seen among those raised in captivity. 4 - I have a friend - a fisher of discs on the upper Rio Negro - He said that sometimes, between discs that collected, came some exceptionally large - the size of a plate and ratified, "the great dish." Unfortunately I do not know if he is still my friend or the anaconda already ate, because two years ago we have no contact. HORMONAL FACTORS Growth hormone, GH or somatotropin is a major responsibility for the development of the fish, as it promotes anabolic processes for the growth of muscles and bones and the physical and functional development of the viscera. Several factors may inhibit the production of GH, including an old acquaintance: "stress". It is very common to find ornamental fish being forced to live under stress, sometimes throughout their life. And what are the most common situations of stress our fish: a) water with physicochemical parameters incompatible with the species; b) a high concentration of organic matter; c) thermal shock; d) reduction in the concentration of dissolved oxygen; e) inadequate conditioning; f) nutritional deficiency; g) excessive or improper medications, especially antibiotics; h) overpopulation, and i) shock in physical-chemical parameters (pH and DH). All of the icons above are barriers to the healthy development of our fish. "And which of us never undergone one of these situations, through carelessness, through forgetfulness, sickness, among others." It is noteworthy, however, that in nature the fish also undergo stressful situations, however, they usually are temporary, such as: attack by a predator; contending for leadership, disputes over food, etc, in all these situations the loser or be eaten or away, closing in this way, the state of stress. The WATER TEMPERATURE This is another parameter that should be considered in the growth process, because, being pecilotérmicos, fish regulate their body temperature to the water temperature. Thus, all activities are physiological digestion, respiration, reproduction, feeding, etc., are directly influenced by temperature. Each species has an optimum temperature for development, and that are above or below those influencing also directly the growth of the fish. LIGHTING It is evident that the sunlight is the most appropriate, but we can not simply put the tank in the sun and ready because unleash a series of undesirable processes, both for the fish and for hobbyists. In nature, the fish are exposed to direct sunlight as much as need, however, there are places where they take refuge when there is this need. Lighting is important for the absorption of some vitamins such as vitamin D, which regulates bone metabolism and deposition of calcium in bones, an important factor for growth. The vitamin D promotes the absorption of calcium is necessary to achieve this, the body exposure to light. CONCLUSION: As we have seen these are just some of the parameters that we must study to understand why our fish do not grow as much as those who are in their habitats. I think this topic would make an excellent thesis in the area of animal nutrition. Wilson Vianna Studies Center Aquariofilia-CEA Ornamental Aquaculture Association of the State of Rio de Janeiro-AQUORIO [email protected]
Posted on: Fri, 13 Sep 2013 18:16:47 +0000
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