Boas
Já há um tempo que descobri este artigo sobre a hidropsia nos peixes.
Acho que vos pode ajudar a entender melhor a doença.
Espero que entendam inglês, ou então Google tradutor please!
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"Question: Hi guys,I have a beautiful purple female betta fish. I've had her for about a year now. She has a very bad case of abdominal dropsy. Her abdomin is bloated, but her scales don't stick out that much. Her left gill functions when I give her once-weekly salt baths, but other than that it has very little movement. The fish is in a small container so I'll know where she is if she dies. I lost a fish to this EXACT thing in August (even the gill thing). Does anyone have any suggestions? Is this painful and should I perform euthanization?Also, please check out my FishGeeks.com question about this fish. It has pictures! http://www.aquaria.info/index.php?name= ... sc&start=0
Answer: Sadly to inform you but dropsy is not able to be cured, as it is not an illness, but the symptom of a larger problem. Generally when a fish is subjected to exntensive nitrate and nitrtite exposure, slowly but surely their internal organs take a toll. As a popular form of debate in the aquarium world, without strong factual proof, nobody is truly able to determine the cause of Dropsy in ornamental fish, though we are well aware of the cause, and effect of this horrible, horrible ailment. Many will argue that Dropsy can be cured, when in truth all that is happening is Dropsy is being treated. As once again it is the symptom of a larger problem, when and if your fish goes back to normal, the changes of it again turning dropsy increasy twenty fold, if not more. What is happening to your fish is it has come across problems with what we call osmo-regulation. From grade 10 you may recalll the simple methods of Osmosis, perhaps if you took science further than grade 10, you may have a much better understanding of this process. As salts in your water come into contact with fish, the elemental action of osmosis takes place, the solution with a more dense concentration of a substance will force itself into an area of lower concentration. More than this, your fish produces and holds wastes inside of itself as a natural method of Osmo-regulation, since the wastes produced by your fish are highly concentrated in salts, the fish will hold and discard the neccessary amount of waste in order to maintain its osmo-regulation.Now when internal organs fail, namely the kidneys, the filtration of the toxins and waste inside of your fish goes downhill, Suddenly your fish begins to hold much more waste inside of itself than neccessary, due to its kidney malfunctions will cause the surrounding water to invade your fish, causing it to grossly swell. Once your fish has been invaded by aquarium water in the most painfull manner imaginable, what you would compare to a hair folicle on a person, on a fish there is also a small pouch in its flesh housing the root of the scale. These pouches fill with water, and cause the scales to lift from the body and protrude outwards. This is extremely painful for your fish and in my own humbled oppinion, your fish is just starting one of its most epic battles, and it has little to no chance of winning. It may kick dropsy out and win the war, but then kidney faliure will strike again in 2 weeks, and your fish will be right back into the heat, if again it succeeds to ward off Dropsy, maybe it wont come back for a month... But it usually does come back, and everytime, your fish is weaker and less able to be helped. Since the underlying cause is under debate as to weather or not the heart beating irradically is causing the liver and kidneys to malfunction, or weather or not it is a direct kidney and liver failiure, everyone can mutually agree that it IS faliure of internal organs bringing this on, which respectfully will classify your fish as one with permanently damaged internal organs.As mentioned, I for one more than believe, Know that dropsy is incurable, that it is only a symptom, and nothing anywhere close to the cause, this animal in my own sad mind should be culled and put to fish heaven to reduce its suffering even after it wards off dropsy, it will get it again, it will suffer even more, and it is rightfully unfair to the animal to make it endure such things. However I do also respect the fact that this is a decision to be made by the fish owner and not some person off of the internet. For this reason I will also tell you that the only "Successful" manner I've ever heard or seen dropsy controlled with is excessive amounts of aquarium salt to manually regulate the Osmosis in the tank. This can only be done with a hospital tank, as you will easily destroy any fish which is properly regulating osmosis within their bodies. More than this, no medications have ever been linked to the successful remedy of Dropsy, also the damage inflicted onto the internal organs that brought it on is usually always poor water quality. I strongly reccomend you obtain a master water testing kit that will measure pH, Ammonia (NH3/NH4+), Nitrate (NO3-) and Nitrite (NO2-).Having this test kit will permit you to closely manage the level of nitrogen isotopes damaging your fish, which I surely promise is the culprit of your situation. Please also take note that both nitrate and nitrite have extensive halflives, and truly Nitrite is only effectively removed from your tank water through water changes. I hope this helps, and I am sorry for not having "Good" news. But hopefully from reading this we will be able to avoid this happening to your fishes in the future.
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A tão falada OSMORREGULAÇÃO.
Osmorregulação é a capacidade que alguns animais possuem em manter a pressão osmótica constante independentemente da do meio externo, dentro de uma determinada faixa de variação.
Um animal que viva num ambiente de água doce tem fluidos corporais hipertónicos - isto é, tem tendência a receber água, que passa, por osmose, do meio onde está mergulhado para o seu interior. Se não houvesse alguma estratégia de regulação, o animal tenderia a inchar. Assim, estes animais (por exemplo, rãs e peixes de rio) fazem face a este fenómeno não bebendo água e eliminando grandes quantidades de urina muito diluída (tendo, por isso, glomérulos de grandes dimensões nos rins).
Um animal que viva num ambiente de água salgada terá de processar a sua osmorregulação no sentido inverso. Como os seus fluidos corporais são hipotónicos em relação à água do mar (isto é, com uma menor concentração de sais), a água tem tendência a sair naturalmente dos seus corpos, por osmose, o que provocaria a sua morte por desidratação, caso não houvesse alguma forma de regular este processo. Assim, o animal tem glomérulos de pequenas dimensões, de forma a produzir urina isotónica (com o mesmo grau de concentração de sais) em relação à água do mar. Para compensar esta perda de água através da urina, estes animais bebem grandes quantidades de água. Note-se que, pelo senso comum, pareceria mais lógico que fossem os peixes de água doce os que beberiam água - efectivamente, são os de água salgada que o fazem.
Fonte: pt.wikipedia.org
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