魟鱼的故事（中英文对照）

泥鳅

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

泥鳅

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

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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.

泥鳅

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.

泥鳅

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

泥鳅

最近几年，淡水魟变得越来越容易得到和受欢迎，水族箱也变得越来越大、越来越便宜，这让它们合理的变成家庭养殖户爱好者的宠物。尽管世界上几大主要河流也有魟群，但是很多变异的虹鱼在亚马逊河流及其相关河流流域被发现，从秘鲁和哥仑比亚西面至巴西东北方向的亚马逊出口.一些魟也被发现于与亚马逊无关联的南美热带雨林。魟鱼是极其原始的物种，它的物种进化可追溯自300多万年前。

在南美河域最常见的魟是江魟，也有一些至今为止知道很少的中国魟。

看起来所有的亚马逊魟和太平洋魟最密切相关。他们的隔离发生在1500万年前安第斯山极速上升的时候，这阻止了河流的向西流动，迫使河流一路东流至大西洋，使很多魟封闭在新的流域里。这种隔离和亚马逊河域的热带气候、水平面的季节性的巨大变化创造了理想的环境和利于进化的巨大压力，所以仅在一个系统就发现了巨大数量的魟。即使单个物种在这整条河流被发现，例如Motoros和Histrix都是多态的，每一个都展示了它们多样的颜色、栖息模式和在不同地区可微妙改变的饮食习惯。
小心魟鱼的刺：魟鱼之所以被这样叫是因为长于它们尾巴上的锯齿状的，像剑般的刺，这些刺平躺到其尾部，它的刺一般覆盖在皮层下面而且不容易被看到，这种有效的防卫武器是由蛋白质复合体组成的，而且当魟鱼的皮鞘破裂的时候，一种有毒的液体会随之释放。如果魟鱼的刺刺到你，它会引起大范围的水泡和剧烈的燃烧疼痛感。急救措施是把伤口浸泡在可以忍受的高温水中，这可以帮助中性毒液。这个方法也不总是可行，特别是在河里的时候。传统的急救措施是把尿撒在伤口上，这样之所以可行是因为尿不仅是热的，无菌的而且是微酸性的。亚马逊的名俗说，必须有一个处女尿在伤口上，但是也有了这个笑话，有一个好消息和一个坏消息。。。巴西有没有处女。即使有巨大的疼痛，也很少会致命，除非伤口是距离胸部很近。据记载，有一个悲剧的事件，一个渔民正在把他抓到的魟鱼拉到船上，幸运的是魟鱼不像平常一样带有攻击性，即使魟鱼可以通过鞭打尾巴或者用尾巴刺穿来很准确的定位它们的目标。在亚马逊河，很多伤亡事件发生在魟鱼藏在沙滩上晒太阳或者是在白天打盹儿，所以很多人呗刺到，都是在脚上或者是腿的下半部分。相比于在沙滩上，魟鱼更倾向于爬行，所以当地人们都知道拖着脚慢慢走或者是用竹子戳进沙子里，因此魟鱼可以感觉到这个动作然后平安无事的让路。对于业余爱好者情况就相反了，他们经常在清理贮水池或者移动魟鱼的混乱情况下被攻击到手或者手臂。有时候这是纯粹的意外，其他的是在处理魟鱼的时候太粗心。即使是一只已经死了的魟鱼，它的刺也是有毒的而且非常锋利的。
一只henlii,leopoldi或者是珍珠魟鱼活着的时候在水族市场出售的价值高于作为一个村子一个星期的肉食或者是产奶几年。例外的是，大部分魟鱼物种的数量在它们的栖息地都过于丰富，所以它们都视为害虫，这也导致了在淡季或者是当水族贸易出口已经盈满的时候，走私魟鱼是可以的这种太多的产生。供需法则刺激市场，最后的零售价格增加激励。走私魟鱼经常是比那些通过合法渠道出口的更贵而且通常是不健康的，因为通过走私这种方法通常还要忍耐额外的考验。有许多关于魟鱼被藏在汽油罐或者是船板下面的故事，幸运的是人们的口袋装不下魟鱼。


水槽的尺寸、水槽中的伴侣和饲养
在水族管里饲养魟鱼的吸引之一是因为它们的习性和智慧。一条健康的魟鱼可以很快学会如何去辨认饲养它的主人的手。人工饲养一条大的魟鱼对于那些饲养者来说是一件很值得的互动式的体验。当然，它们与众不同的外表和明显的美丽和特点也增加了乐趣。大部分魟鱼成长得很快，而且如果照顾得当的话它们会长大到一个小槽已经容不下的尺度。即使是在成长的初期，它们也需要一个大槽。理想上，它们应该当作单独的一个物种被饲养，换言之，它们必须单独饲养。和其他物种一起饲养可能是有危险的。更受欢迎的水槽中的伴侣之一是龙鱼，但是如果它们的尺度和魟鱼不相协调也会造成问题。伴生种的一般法则是“如果魟鱼的大小和它的嘴巴大小相吻合，那么迟早它会吃掉魟鱼”。如果龙鱼太大了，那么它可能会攻击魟鱼，然后也肯定会把魟鱼当成食物给吃了。另一方面，如果龙鱼没有足够大，那么可能最后魟鱼也会吃了它。当我的一个朋友的一条22英寸的虎纹魟鱼吃了他那条10英寸长价值2000美元的亚洲红色龙鱼的时候，他很沉重的发现了这个情况。异形鱼能够呈现出同样的问题，它们可能会被魟鱼吃掉或者是在魟鱼上身的粘液外表吃免费的午餐然后引起压力或者是伤口的继发感染从而造成魟鱼的死亡。魟鱼健康的时候有着狼吞虎咽的胃口，可以享受一系列的食物。早期吃的是活着的食物。加州的蠕虫和蚯蚓都被贪婪的吮吸。鬼虾是一种经常让我的更小的魟鱼欢快的旋转的食物。一旦习惯了，大部分魟鱼也会吞食新鲜急冻虾和其他类似的食物。胡瓜鱼，鲑鱼片，各种贝类和其他海鲜食物也是可以接受的，但是有一些是很肮脏的，因此必须先测试或者是仅仅在大换水的时候饲养。魟鱼也可以接受家常菜谱。人工饲养魟鱼是最令人满意的经验之一，保证即使是最最有成见的人也会从其口中听到赞叹的“喔”。魟鱼不总是刺人的，但是当它被饲养的时候它也会高兴地击水。所以当人工饲养的时候总是注意到魟鱼的尾巴在哪里是很重要的，这样魟鱼也可以意识到你所以它不会受惊。过了一会，魟鱼可以变得很驯服的，允许人们的安抚，积极研究可能在你手中的食物。

水参数
亚马逊河域的水都是软水，几乎没有矿物。只有巨大的降水量阻止了PH值的急剧下降。它们大部分栖息地的PH值都在6.5分左右。当适应新环境了，大部分的魟鱼可以生存在自来水的环境下，而不要求广泛的化学物质来维持它们。但是，因为它们吃很多，因此排泄物也很多，所以好的维修系统来保持水的干净和过滤器来清除污泥是很重要的。我建议每周至少换两次浓度不小于25%的年龄水。最重要的水槽没有半点拥挤。魟鱼容易氨和硝酸盐中毒而造成器官损伤，所以通过定期换水和良好的生物过滤来监测氨和硝酸盐的浓度，保持其浓度在恒零的状态下是很重要的。Ross博士在他书里谈到氨中毒是导致魟鱼安静死亡的主要原因。这种伤害通常是在原有的情况下造成的，在箱子里超过36个小时。一条魟鱼因为这个原因死亡一般会占有两三个星期，因为它拒绝进食，然后逐渐消瘦或者是因为体内毒素而死亡，所以有时候很难理解在恶劣的水中和最后的死亡之间的联系。

使你的新魟鱼适应新环境，装饰水槽
有一些魟鱼比其他的更敏感，众所周知，副河魟属和小眼睛种类比potamotrygons更难养。普遍知道的和亚马逊河域水土不服的是histrix,motoros还有reticulated. 很多人通过分沫器等到“茶杯”这个名字不仅仅单纯指它们的小尺寸，也和知道它们的物种没有重要的关系。这些通常是介绍第一次饲养魟鱼，因为它们和异国魟鱼相比是廉价的。其中一些很像异国的物种，例如Leopoldi，习性都是很强壮很活跃而且带有攻击性的，其他的，像虎纹魟鱼看起来就是更腼腆，但是这些都是迷惑人的，因为很多物种在适应环境或者是在一个舒适的环境下都是很活跃的。大部分人都不必担心使魟鱼适应出口。如果你高兴你得到的魟鱼是健康的，那么让它适应你的水槽或者水池也不难。几英尺的航空油管和虹吸管和你的新魟鱼一起顺着水槽进入盒子中是你所需要的所有东西。当盒子里的水在魟鱼进入的时候溢出来，那么原来的水被稀释了。这将花费30分钟到1个小时的时间。水槽的水和盒子的水的参数差异越大，你应该越慢做出改变。当尽可能多的溢出箱子的水的时候，把箱子和魟鱼轻放在水槽中，然后允许魟鱼游出盒子然后回到它的新家。我保持我的池子无底，但是大部分的爱好者更愿意有基底。避免使用任何尖锐的，例如含有硝酸盐的沙子是很重要的，因为这会撕碎魟鱼的底部，然后会造成悄悄的感染，导致魟鱼的死亡。

逆游的鱼

楼主很给力，竟然还有中英结合{:soso_e183:}