魟魚的故事（中英文對照）

泥鰍

An Introduction to Freshwater Stingrays

Aquarticles

The author with a few of his stingrays

            In the last few years freshwater rays have become increasingly available and popular and tanks have become larger and cheaper, making them a reasonable pet for the dedicated home aquarist. Although some other major rivers around the world have ray populations, most freshwater ray species are found in Amazonia, and as with its other flora and fauna, the Amazon system has an abundance of ray variants found all along the river and in many of its tributaries, from Peru and Colombia in the West to the mouth of the Amazon in North Eastern Brazil. Some ray species are also found in other tropical South American rivers with no direct connection to the Amazon. Stingrays are very ancient species, tracing their evolutionary history as far back as 300 million years.

Evolutionary History

The most commonly found species in South American rivers are Potamotrygon. There are also rays known as China or Coly rays, about which little is known at this time.

P. motoro - Peru

Large China Ray middle, P. leopoldi top, P. motoro bottom

Estrella Ray center, Peru

       It is thought that all of these Amazon rays are most closely related to Pacific Marine rays. Their isolation would have occurred when the Andes Mountains rapidly rose up about 15 million years ago, blocking the Westward flow of the river as it then was and forcing it to flow east all the way to the Atlantic, trapping many rays in the new system. This isolation and the Amazon’s tropical climate and seasonal massive changes in water levels created ideal circumstances and great pressure for evolutionary changes, as represented by the huge variety of stingrays found in just the one system. Even individual species that are found along the whole river, such as Motoros and Histrix, are polymorphic, each exhibiting their own wide range of colors and patterns as habitat and available diet change subtly between regions.

Scobina Ray

Flower Ray from Venezuela/Columbia

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A word of warning about a stingray's stinger
Stingrays are so-called for their serrated, dagger-like stinger located on the top of and lying flat towards the end of the tail. Usually sheathed in a layer of skin and not always easy to see, this effective defense weapon is made of a protein complex , and is accompanied by a nasty venom usually released when the skin sheath of the stinger is ruptured. If the stinger cuts you it can cause large local blisters and intense burning throbbing pain. The immediate treatment for this is to immerse the wound in water as hot as can be tolerated, which helps to neutralize the toxins. This is not always possible, especially on the river. The traditional first aid treatment there is to urinate on the wound which works because urine is both hot , sterile and slightly acidic. Amazon folklore says that it must be a virgin who pees on the wound, leading to the joke 'there is good news and bad news......there are no virgins in Brazil'. Although extremely painful the ‘sting’ is rarely fatal unless by some bizarre accident it is in the chest near the heart, a tragic event which has been recorded as a fisherman was pulling a caught ray onto his boat. Fortunately for the aquarist even the feistiest ray is not normally aggressive with its stinger, though rays can be very accurate with their aim, either slashing or stabbing with their powerful tails. In Amazonia most casualties happen when a ray is stepped on as it hides under the sand basking and snoozing during the day and so most stings are on the feet or lower leg. Rays would much prefer to move than be stepped on so locals know to shuffle their feet or poke the sand ahead of them with a stick when in the water, so that a ray can sense the motion and move out of the way without incident. For hobbyists it is the opposite, most people get hit on the hand or arm as they mess around in the aquarium while cleaning the tank or moving the ray. Sometimes it is a pure accident, others it is from carelessness handling the ray. Even on a dead ray the stinger is still toxic and very sharp.
Types of rays kept by hobbyists
The majority of rays kept by hobbyists these days , and the main focus here, are Potamotrygonidae, species of Elasmobranchs which are found exclusively in freshwater and includes more than 22 distinct varieties. At this time there is a lot to be learned about the relationship between these different varieties, whether they are sub-species or how closely they are related to each other. There is a dramatic and beautiful range of size , patterns and colors between them . Black rays with striking polka-dot patterns, such as the Leopoldi, Henlii and the less common small spot Itaituba Black rays are found in Brazilian Southern Amazonian clear water rivers. Two of the more dramatically patterned types are Tiger rays, named for their striking patterns and the markings on their tails, found in Peruvian Amazonia and the similarly patterned Flower rays, found in Northern Amazonia in some of the Colombia/Venezuela/Brazil border region rivers. There are many other local ray variants that are not as beautifully patterned but still are interesting. Castexi rays, one of the most polymorphic rays, with large array of distinctly different body patterns, are mostly found in the Western regions of Amazonia, with morphs such as Otorongo
(translated: Jaguar), Motello ( tortoise), Hawaiian, Tigrinus and others, all named for their beautiful patterns.

Pearl Rays

2011-12-12 14:41:24 上傳
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Itaituba Ray

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Rare P 14 Variant

The debate on species differentiation
There is some debate concerning the different variants within species like Castexi and also the Black rays about how closely related to each other they may be. Whether they are truly separate species or are simply color morphs from slightly different habitats that would be expected to produce slightly different characteristics. Leopoldi, Henlii and Itaituba Black rays are prime examples often invoked in this debate, and their ability to easily interbreed throws more confusion on the whole subject. They are normally found in, and separated by, different Amazon tributaries. Leopoldi are found in the clear waters of the Xingu and Henlii are found in the waters of the Tocantins, clearly separate habitats according to the maps, but when the high water season is there it is impossible to know how different species are moved around by the massive inundation of floodwaters or if & how they migrate into different systems when water levels permit, only to become isolated again when the seasonal floods recede to lower levels. So it may be possible to find a species that may normally be only found in Peru or Colombia all the way down river in Brazil. It may also be that many of the species are in the middle of an evolutionary spurt, developing into new species. ‘Hybridization’ ( if they are actually separate sub-species) also seems to be a regular occurrence when natural circumstances permit and viable offspring suggests that Potamotrygon are not separate species.

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Newly arrived young leopoldi - Brazil - Xingu

Flower Rays middle, leopoldi to right

Estrella and leopldi

Stingrays - a pest to some, a beauty to others
"In the Amazon all things are possible". During the low water season, when fish are concentrated in small areas and main river and Igarape channels, it is relatively safe to travel to remote areas to investigate ray population distributions; but this season is relatively short, often as little as 4 or 5 months only before the new rains start and the water levels rapidly and dramatically rise again. Much of Amazonia is still unexplored, and river courses change making it impossible to be absolute when it comes to discussing Amazonian fish populations and distributions. Some ray populations are booming to the point where they are considered a pest on the sandy beaches of the river. People are employed on popular river beaches in Brazil to keep the beaches clear of the rays, which tend to congregate in ‘dormitories’ to bask just under the sand in shallow water during the day, just the place where bathers walk . Basically those rays are killed as a pest and left to rot and feed the scavengers. There is a certain irony in this as those same rays could be sold alive to the aquarium trade instead and generate income. Some ray varieties are only found in limited areas and are not common, such as ‘Pearl’ rays. Rays are also an important local food fish . These are both contributing reasons for annual stingray quotas out of Brazil. However, these quotas often produce paradoxical facts. As a food fish many rays are worth much more alive to the aquarium trade than they are as food. One Henlii , Leopoldi, or Pearl ray, sold alive, is usually worth more on the aquarium market than a meat animal that might feed a whole village for a week or give milk for a few years. With a few exceptions, most ray species are plentiful in their native habitats and are considered pests, which contributes to an attitude that it is OK to smuggle rays out during the off-season or when all the quotas for aquarium export have already been filled. The laws of supply and demand fuel this market, with the final retail price for them adding incentive. Smuggled rays are often more expensive and usually less healthy than those that are exported through legal channels because of the extra ordeal those smuggled rays have to endure when exported this way. There are many tales of rays (and other smuggled flora and fauna) being hidden inside adapted gasoline cans or under floorboards aboard fishing boats. Luckily they don’t fit into people’s pockets.

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Tiger Ray

Otorongo Ray

Tank size, tank mates, and feeding
One of the attractions for keeping rays in the aquarium is their behavior and intelligence. A healthy ray can learn very quickly how to recognize and hand feed from its owner. Hand feeding a large ray is a rewarding interactive experience for all those who do it. Of course, their ‘other-worldly’ appearance and their obvious beauty and character add to the pleasure. Most rays grow fast and if properly cared for will quickly grow to a size that is not suitable for a small tank . They require a large tank even at the beginning of their residency. Ideally they are kept as a single species, in other words they should be kept alone. Mixing other species can be precarious. One of the more popular tankmates are Arowanas, but if they are not matched for size with the rays then there can be problems. As a general rule of thumb when it comes to companion species ,"if a ray can fit it in its’ mouth then sooner or later it will eat it". If the Arowana is too big then it might attack the ray and will certainly beat the ray to food. On the other hand if the Arowana is not big enough then there is a good chance that eventually the ray will eat it. A friend of mine found this out the hard way when his 22" disc Tiger ray ate his 10" long $2000 red Asian Arowana. Plecos can present a similar problem, either they will be eaten by the ray or they will take free meals from the rays upper body slime coat, causing stress and possible secondary infections in the wounds and eventual death for the ray. Rays when healthy have voracious appetites and enjoy a range of foods. The easiest are live foods. California blackworms and earthworms are greedily sucked down. Ghost shrimp are a favorite food that often sends my smaller rays literally spinning with joy. Once used to it, most rays will also devour fresh frozen shrimp and other similar foods. Smelt , Salmon pieces, various shellfish and other kinds of seafood are often accepted, but some can be very messy and should be tested first or only fed just before a large water change. Rays can also be adapted to homemade recipes and prepared sinking commercial foods. Hand feeding your ray is one of the most rewarding experiences guaranteed to get a "WOW" from even the most jaded person. A ray is not inclined to sting, but can thrash about with happiness when being fed so when hand feeding it is important to be aware of where the rays tail is at all times and that the ray also be aware of you so that it won’t be startled. After a while rays can become very tame, allowing petting and actively investigating your hand for possible food.

Large China Ray

Water parameters
Amazonian rivers are all very soft water, with few minerals at all. Only the massive volumes of rainfall prevents the pH from falling sharply. Most of their habitat is around the pH 6.5 mark. When properly acclimated most rays can thrive in our tap water and do not require extensive chemistry to maintain them. However, they eat a lot and consequently excrete a lot so good husbandry is important in order to keep the water clean and the filters clear from sludge buildup. I recommend at least 2 water changes each week of at least 25%, using aged water. More if the tank is the least bit crowded. Rays are susceptible to organ damage from Ammonia and Nitrates poisoning so it is essential to monitor those levels and maintain them at constant zero through regular water changes and good biological filtration. Ammonia poisoning is one of the main causes of the ‘silent death’ as spoken of by Dr. Ross in his books. The damage is often done in original transit, which is often more than 36 hours in a box . A ray may take up to a couple of weeks to die from this, as it refuses food and either wastes away or dies from the internal toxins, and so it is sometimes hard to understand the linkage between shipping in bad water and the eventual death.
Acclimating your new rays, tank decoration
Some rays are more sensitive than others, the Paratrygon and China (small eyed) species are notoriously more difficult to keep than the Potamotrygons. Common popular species that are endemic to the Amazon are Histrix and Motoros and Reticulated. Many arrive under the catch-all name of ‘Teacup’ but this really only refers to their juvenile size and has no significance for knowing their species. These are often a first introduction to keeping rays as they are inexpensive compared to the more exotic rays. Some of those more exotic looking species, such as the Leopoldi, are very hardy and very active and aggressive in their behavior, others , like the Menchacai (Tiger) rays are thought of as being more shy, but this can be deceptive as most species are very active once they are properly acclimated and in a comfortable environment. Most people will never have to worry acclimating rays direct from import. If you are happy that the ray you are acquiring is healthy then acclimation to your tank or pool is not difficult. A few feet of airline tubing to siphon water slowly from the tank into the box/bag with your new ray are all that is needed. As the bag fills remove water until the ray is in tank water and all the original bag water has been diluted out. This takes from 30 minutes to an hour. The greater the differences in parameters between the tank water and the bag water the slower you should make the change. Once this is done remove as much of the water in the bag as possible and gently put the bag and ray into the tank and allow the ray to swim out of the bag into its new home. I keep my pools bare-bottomed but most hobbyists prefer a biotopical look and want substrate. It is important to avoid using anything sharp, such as sand that contains silicates, as this will tend to shred the rays underbody, allowing an infection to creep in, often leading to death of the ray. Estes is a brand name sand that is coated to make it smooth and is available in a variety of colors and is very suitable. The few times I have used a substrate I have chosen something to compliment my ray. For Black rays I use a black sand. Rays will tend to adjust their body color tone to blend in with their background, tending to get either noticeably lighter or darker over a period of a few days to a few weeks. Rays have relatively large brains and are one of the most intelligent of aquatic animals. A ‘dressed’ aquarium can help keep it amused, Driftwood and rocks to search around for food provides plenty of entertainment.
Breeding
Gender identification is simple. Just like their relatives Sharks and marine Rays, male freshwater stingrays have claspers, one on either side of the base of the tail and slightly underneath. In sexually mature males these are easily visible from above and with immature young they can be easily seen from their underside. Females do not have claspers. When mature enough to breed rays reproduce by internal fertilization and give birth to live young after a gestation period of approximately 3 months. ‘Pups’ are usually born in litters of from 2 to 8, depending upon the age and size of the rays involved. While still not a common event in the home aquarium several stingray enthusiasts and many large public aquariums around the world are now successfully breeding many varieties. As with all animals, breeding is a biological imperative for rays that only requires enough space and plenty of good food along with reasonable aquarium conditions and good husbandry to make your pets comfortable . This also makes the aquarium more enjoyable to watch and interact with for the already entranced aquarist.

Large male Motoro center, young leopoldi sides

泥鰍

最近幾年，淡水魟變得越來越容易得到和受歡迎，水族箱也變得越來越大、越來越便宜，這讓它們合理的變成家庭養殖戶愛好者的寵物。盡管世界上幾大主要河流也有魟群，但是很多變異的虹魚在亞馬遜河流及其相關河流流域被發現，從秘魯和哥侖比亞西面至巴西東北方向的亞馬遜出口.一些魟也被發現于與亞馬遜無關聯的南美熱帶雨林。魟魚是極其原始的物種，它的物種進化可追溯自300多萬年前。

在南美河域最常見的魟是江魟，也有一些至今為止知道很少的中國魟。

看起來所有的亞馬遜魟和太平洋魟最密切相關。他們的隔離發生在1500萬年前安第斯山極速上升的時候，這阻止了河流的向西流動，迫使河流一路東流至大西洋，使很多魟封閉在新的流域里。這種隔離和亞馬遜河域的熱帶氣候、水平面的季節性的巨大變化創造了理想的環境和利于進化的巨大壓力，所以僅在一個系統就發現了巨大數量的魟。即使單個物種在這整條河流被發現，例如Motoros和Histrix都是多態的，每一個都展示了它們多樣的顏色、棲息模式和在不同地區可微妙改變的飲食習慣。
小心魟魚的刺：魟魚之所以被這樣叫是因為長于它們尾巴上的鋸齒狀的，像劍般的刺，這些刺平躺到其尾部，它的刺一般覆蓋在皮層下面而且不容易被看到，這種有效的防衛武器是由蛋白質復合體組成的，而且當魟魚的皮鞘破裂的時候，一種有毒的液體會隨之釋放。如果魟魚的刺刺到你，它會引起大范圍的水泡和劇烈的燃燒疼痛感。急救措施是把傷口浸泡在可以忍受的高溫水中，這可以幫助中性毒液。這個方法也不總是可行，特別是在河里的時候。傳統的急救措施是把尿撒在傷口上，這樣之所以可行是因為尿不僅是熱的，無菌的而且是微酸性的。亞馬遜的名俗說，必須有一個處女尿在傷口上，但是也有了這個笑話，有一個好消息和一個壞消息。。。巴西有沒有處女。即使有巨大的疼痛，也很少會致命，除非傷口是距離胸部很近。據記載，有一個悲劇的事件，一個漁民正在把他抓到的魟魚拉到船上，幸運的是魟魚不像平常一樣帶有攻擊性，即使魟魚可以通過鞭打尾巴或者用尾巴刺穿來很準確的定位它們的目標。在亞馬遜河，很多傷亡事件發生在魟魚藏在沙灘上曬太陽或者是在白天打盹兒，所以很多人唄刺到，都是在腳上或者是腿的下半部分。相比于在沙灘上，魟魚更傾向于爬行，所以當地人們都知道拖著腳慢慢走或者是用竹子戳進沙子里，因此魟魚可以感覺到這個動作然后平安無事的讓路。對于業余愛好者情況就相反了，他們經常在清理貯水池或者移動魟魚的混亂情況下被攻擊到手或者手臂。有時候這是純粹的意外，其他的是在處理魟魚的時候太粗心。即使是一只已經死了的魟魚，它的刺也是有毒的而且非常鋒利的。
一只henlii,leopoldi或者是珍珠魟魚活著的時候在水族市場出售的價值高于作為一個村子一個星期的肉食或者是產奶幾年。例外的是，大部分魟魚物種的數量在它們的棲息地都過于豐富，所以它們都視為害蟲，這也導致了在淡季或者是當水族貿易出口已經盈滿的時候，走私魟魚是可以的這種太多的產生。供需法則刺激市場，最后的零售價格增加激勵。走私魟魚經常是比那些通過合法渠道出口的更貴而且通常是不健康的，因為通過走私這種方法通常還要忍耐額外的考驗。有許多關于魟魚被藏在汽油罐或者是船板下面的故事，幸運的是人們的口袋裝不下魟魚。


水槽的尺寸、水槽中的伴侶和飼養
在水族管里飼養魟魚的吸引之一是因為它們的習性和智慧。一條健康的魟魚可以很快學會如何去辨認飼養它的主人的手。人工飼養一條大的魟魚對于那些飼養者來說是一件很值得的互動式的體驗。當然，它們與眾不同的外表和明顯的美麗和特點也增加了樂趣。大部分魟魚成長得很快，而且如果照顧得當的話它們會長大到一個小槽已經容不下的尺度。即使是在成長的初期，它們也需要一個大槽。理想上，它們應該當作單獨的一個物種被飼養，換言之，它們必須單獨飼養。和其他物種一起飼養可能是有危險的。更受歡迎的水槽中的伴侶之一是龍魚，但是如果它們的尺度和魟魚不相協調也會造成問題。伴生種的一般法則是“如果魟魚的大小和它的嘴巴大小相吻合，那么遲早它會吃掉魟魚”。如果龍魚太大了，那么它可能會攻擊魟魚，然后也肯定會把魟魚當成食物給吃了。另一方面，如果龍魚沒有足夠大，那么可能最后魟魚也會吃了它。當我的一個朋友的一條22英寸的虎紋魟魚吃了他那條10英寸長價值2000美元的亞洲紅色龍魚的時候，他很沉重的發現了這個情況。異形魚能夠呈現出同樣的問題，它們可能會被魟魚吃掉或者是在魟魚上身的粘液外表吃免費的午餐然后引起壓力或者是傷口的繼發感染從而造成魟魚的死亡。魟魚健康的時候有著狼吞虎咽的胃口，可以享受一系列的食物。早期吃的是活著的食物。加州的蠕蟲和蚯蚓都被貪婪的吮吸。鬼蝦是一種經常讓我的更小的魟魚歡快的旋轉的食物。一旦習慣了，大部分魟魚也會吞食新鮮急凍蝦和其他類似的食物。胡瓜魚，鮭魚片，各種貝類和其他海鮮食物也是可以接受的，但是有一些是很骯臟的，因此必須先測試或者是僅僅在大換水的時候飼養。魟魚也可以接受家常菜譜。人工飼養魟魚是最令人滿意的經驗之一，保證即使是最最有成見的人也會從其口中聽到贊嘆的“喔”。魟魚不總是刺人的，但是當它被飼養的時候它也會高興地擊水。所以當人工飼養的時候總是注意到魟魚的尾巴在哪里是很重要的，這樣魟魚也可以意識到你所以它不會受驚。過了一會，魟魚可以變得很馴服的，允許人們的安撫，積極研究可能在你手中的食物。

水參數
亞馬遜河域的水都是軟水，幾乎沒有礦物。只有巨大的降水量阻止了PH值的急劇下降。它們大部分棲息地的PH值都在6.5分左右。當適應新環境了，大部分的魟魚可以生存在自來水的環境下，而不要求廣泛的化學物質來維持它們。但是，因為它們吃很多，因此排泄物也很多，所以好的維修系統來保持水的干凈和過濾器來清除污泥是很重要的。我建議每周至少換兩次濃度不小于25%的年齡水。最重要的水槽沒有半點擁擠。魟魚容易氨和硝酸鹽中毒而造成器官損傷，所以通過定期換水和良好的生物過濾來監測氨和硝酸鹽的濃度，保持其濃度在恒零的狀態下是很重要的。Ross博士在他書里談到氨中毒是導致魟魚安靜死亡的主要原因。這種傷害通常是在原有的情況下造成的，在箱子里超過36個小時。一條魟魚因為這個原因死亡一般會占有兩三個星期，因為它拒絕進食，然后逐漸消瘦或者是因為體內毒素而死亡，所以有時候很難理解在惡劣的水中和最后的死亡之間的聯系。

使你的新魟魚適應新環境，裝飾水槽
有一些魟魚比其他的更敏感，眾所周知，副河魟屬和小眼睛種類比potamotrygons更難養。普遍知道的和亞馬遜河域水土不服的是histrix,motoros還有reticulated. 很多人通過分沫器等到“茶杯”這個名字不僅僅單純指它們的小尺寸，也和知道它們的物種沒有重要的關系。這些通常是介紹第一次飼養魟魚，因為它們和異國魟魚相比是廉價的。其中一些很像異國的物種，例如Leopoldi，習性都是很強壯很活躍而且帶有攻擊性的，其他的，像虎紋魟魚看起來就是更靦腆，但是這些都是迷惑人的，因為很多物種在適應環境或者是在一個舒適的環境下都是很活躍的。大部分人都不必擔心使魟魚適應出口。如果你高興你得到的魟魚是健康的，那么讓它適應你的水槽或者水池也不難。幾英尺的航空油管和虹吸管和你的新魟魚一起順著水槽進入盒子中是你所需要的所有東西。當盒子里的水在魟魚進入的時候溢出來，那么原來的水被稀釋了。這將花費30分鐘到1個小時的時間。水槽的水和盒子的水的參數差異越大，你應該越慢做出改變。當盡可能多的溢出箱子的水的時候，把箱子和魟魚輕放在水槽中，然后允許魟魚游出盒子然后回到它的新家。我保持我的池子無底，但是大部分的愛好者更愿意有基底。避免使用任何尖銳的，例如含有硝酸鹽的沙子是很重要的，因為這會撕碎魟魚的底部，然后會造成悄悄的感染，導致魟魚的死亡。

逆游的魚

樓主很給力，竟然還有中英結合{:soso_e183:}