Sad Fish

With a head like a fighter-plane cockpit, a Pacific barreleye fish shows off its highly sensitive, barrel-like eyes--topped by green, orblike lenses--in a picture released today but taken in 2004.

The fish, discovered alive in the deep water off California's central coast by the Monterey Bay Aquarium Research Institute (MBARI), is the first specimen of its kind to be found with its soft transparent dome intact.

The 6-inch (15-centimeter) barreleye (Macropinna microstoma) had been known since 1939--but only from mangled specimens dragged to the surface by nets.

For female guppies, there's more to life than making babies.

A new study finds that guppies experience menopause just like humans and other animals. The study is the first demonstration of menopause in fish and raises the question of why some female animals live beyond their fertile years at all.

It was previously thought that fish don't experience menopause because they produce eggs throughout their entire lives. Birds and mammals, in contrast, have a finite number of eggs that they are born with.

Guppies typically reproduce about every 30 days and give birth to litters approximately 20 times throughout their lives. The researchers found that as female guppies aged, they began to skip litters or even stop reproducing for extended periods of time, effectively ceasing to reproduce after a certain age. In other words, the guppies were going through a fish version of menopause.

Living longer to have more babies

David Reznick, a biologist at UC Riverside, and colleagues compared the life history of 240 guppies taken from mountain streams in Trinidad. Some of the guppies were from high-predation environments while others were not. The researchers divided the life history into three segments: birth to first reproduction, first to last reproduction, and last reproduction to death.

In a previous study, Reznick found that guppies from high predation environments live longer and start reproducing at a younger age than those that were at less risk. The current study was meant to explore how and why this happens.

Using evolutionary theory, the researchers were able to make specific predictions based on what they knew about the reproductive life history of guppies.

After giving birth to their litters, female guppies don't stick around to provide maternal care. The researchers therefore predicted that if evolution by natural selection was responsible for the longer lifespan of the high predation guppies, then it should only affect their reproductive years. This is because, from an evolutionary point of view, those are the years that are most crucial for the success of the species. Scientists call an animal's ability to produce offspring "fitness."

"Guppies have no postnatal care for their young, so from a fitness prospective, when they last give birth, they might as well be dead," Reznick told LiveScience. "The only reason for them to live longer would be that different parts of their bodies break down at different rates."

The researchers also predicted that the post-reproductive lifespan--the period after menopause--of both the high- and low-predation guppies would be the same.

The study found both predictions to be true.

"The older fish, after they stop reproducing, do not contribute to the fitness of young fish," Reznick said. "As a result, the post-reproductive period is not influenced by natural selection."

Reznick wonders if the same might be true for other animals, including humans.

For hundred of years, the Siamese Fighting Fish or Betta splendens, has been kept and cultivated by people in Thailand (Siam). Today, the Betta is popular throughout the world – though not for the purpose of fish fighting but as a peaceful aquarium resident. Through years of selective breeding, pet store Bettas look vastly different from their original, wild-caught ancestors. Instead of just a few colors, they can now be purchased in an array of hues including red, blue, turquoise, black, white, yellow, and brown.

In addition, their fins have greatly increased in size and are much more elaborate; among the different types of hybrids available are the Veil Tail, Delta Tail, Half Moon, Double Tail, and Crown Tail. Of course, it is only the males that have the long, elegant fins and do all the fighting. Females have much shorter fins and are not as vividly colored as the males. Interestingly, Bettas are air breathers; they use a unique organ called the labyrinth to process the oxygen in the air and they will die if they are unable to reach the waters surface.

The Betta’s native habitat is the warm, still ponds, swamps and rice paddies of Southeast Asia. There, among the leaves and branches of the dense undergrowth, these carnivorous fish hunt for small insects and larvae.

Although the Bettas found in pet stores today have been captive bred, they should be kept in conditions that mimic their ancestor’s natural environment. Therefore, an aquarium (minimum size of 10 gallons) that is decorated with several plants and that has gentle water movement will suit them best. A cover, with a few small openings to allow air circulation, should also be provided to prevent them from jumping out.

Bettas like warmer temperatures so the water in the aquarium should be kept between 76-85 F with a slightly acidic pH of 6.5-7.0. Their diet should consist primarily of meaty foods such as brine shrimp, bloodworms, freeze-dried tubifex worms, etc. Bettas can grow to 3 inches long and live for up to 3 years if cared for properly. As far as tank mates are concerned, Bettas get along fine with most fishes; but do not keep them with aggressive species or any that are prone to pick at their beautiful fins. Male Bettas can be kept together in the same tank only if they are partitioned off from each other – otherwise you can expect some shredded fins, missing scales and not-so-nice looking fish!

A very intelligent fish that can recognize its owner, the heavily built Oscar is an all-time favorite among aquarium hobbyists. Originally imported from South America, most Oscars for sale are now tank-bred. A large aquarium of at least 70 gallons is required to house a pair of Oscars.

The Oscar fish has his own ideas on how to decorate what he considers his home (your aquarium!) he will grab any object including small rocks and plants (doesn't care whether they are natural or artificial) and spit them out of the tank if he doesn't like them -a deep sand bottom and few large rocks will save you a lot of headaches.- Oscars have hearty appetites and should only be kept with fish that are the same size or larger; smaller fish soon become a quick snack for the Oscar. Other South American cichlids and large catfish make good tankmates.

Occasionally the Oscar will pretend he's dying and will lay down on the bottom of the aquarium (don't worry oscars are excellent actors) he will wait for small fishes to get closer; although some people recommend feeding them live goldfish and guppies I personally do not like the idea as you take a real chance of introducing diseases, instead you can feed them vegetarian cichlid pellet, peas, lettuce (this is important to prevent hith disease) blended beef heart, earthworms and shrimps.

One of the most universally served fish in restaurants throughout the world is tuna. Aside from being delicious and popular, tuna is extremely versatile. However, for all its culinary glory, tuna remains a controversial fish. Catching practices have been criticized for their cruelty to other marine species. Another problemis that the wild tuna population is hard to sustain, because most of the species grow very slowly. And studies have shown that tuna, especially the Bluefin variety, can be high in toxins like mercury. So, what to do? Try something new! Here are some suggestions:

* Haddock: This rapidly reproducing fish rivals tuna in popularity and distribution throughout the world, because it is tender and flaky. We commonly associate Haddock with fried preparations, such as the British classic, fish and chips. Young haddock are sold as "scrod" in New England. I love poaching it and/or mincing the filets for croquettes. I also recommend breading and baking the filets or steaming them over a bed of greens. (Careful: Since haddock is so flaky, it falls apart when sautéed or over-handled with a spatula.)
* Pollack: Though Pollock is the most heavily distributed fish for human consumption, it is fast-growing and considered one of the most sustainable fish. Best of all, it has virtually no detectable levels of mercury. Pollack proliferates North Atlantic and Artic waters. My favorite is whole-smoked Pollack, often available in seafood specialty stores.
* Sardines: While not immensely popular in the United States, fresh sardines can be delicious. Sardines are actually a few species of herring. I love buying whole fresh sardines (gutted) at my local seafood market, rubbing them gently with olive oil, seasoning them with salt and pepper, and then roasting them in the oven at 500°F for 5-7 minutes. Drizzle with lemon or orange juice and a splash of Sherry vinegar for acidity.
* Mackerel: Like sardines, mackerel also include several species of fish, including the King mackerel, Spanish mackerel and Atlantic mackerel. Mackerel is rich in Omega-3s and has a naturally smoky flavor. I recommend Atlantic Mackerel. Treat them to a similar preparation as the sardines (salt, pepper, lemon, olive oil, and whole sprigs of fresh thyme). Or try another route: First, roast some potatoes in the oven. (try Purple Majesty potatoes. They are a rich blue color and have a creamy flesh, as if they were grown with a little butter in the soil!) When the potatoes are tender, raise the oven temperature to 500F and place the fish filets (with or without skin) on top of the potatoes. Cook for 5-7 minutes, depending on the size of the fish. Serve with fresh lime or a drizzle of Balsamic.

1. The colder the water, the more nutritious and safer the fish. Coldwater fish, such as salmon and tuna, contain more of the omega 3 fatty acids, DHA and EPA than do fish from warmer waters, such as catfish, red snapper, trout, and pike. As a general guide, the warmer the water, the lower the oil content of the fish. Ocean fish tend to be safer than lake fish, which are more likely to contain traces of environmental pollutants.

2. Fish is good heart food. Some fish are high in heart-friendly cholesterol-lowering fish oils. Omega-3 fatty acids, especially DHA, have been linked to reducing total blood fats, reducing LDL (bad) cholesterol, and raising HDL (good) cholesterol. Fish oils rich in DHA are good for the heart. They keep the platelets, the saturated fatty acids, and cholesterol from sticking together and clogging arteries, contributing to heart attacks and stroke. After all, fish fats are called oils, meaning they flow rather than sit. One study showed that one serving of salmon per week cut the risk of heart attack in half. In another study, researchers who followed more then 20,000 male physicians between 40 and 84 years of age for eleven years found that those who ate fish once a week were 52 percent less likely to die of a fatal cardiac arrhythmia (irregular heart beats) than those who consumed fish less than once a month. The heart-friendly effects of fish oil seems to be related to their ability to lower total cholesterol, raise HDL (good cholesterol), and lower LDL (bad cholesterol).

Since fish fat actually seems to be good for people, might this cast some doubt on the conventional nutritional wisdom that a high fat diet contributes to heart disease? It would probably be more accurate to say that right fats contribute to heart health, wrong fats contribute to heart disease. As evidence look at the Eskimos, who have a diet very high in fat, yet have lower levels of cardiovascular disease. Is this because they eat a lot of fish? (It may also be true that Eskimos have a genetically different way of metabolizing extra fats that protects their heart.) It is also true that most people who eat fish regularly have healthier lifestyles and diet in general.

3. Fish is good brain food. Not only is fish good for the heart, it's good for the head. Fish oils are healthy because they contain the two essential omega 3 fatty acids: DHA, which are particularly valuable as nutrients for the cells of the brain and nervous system, the eyes, and the adrenal and sex glands. Come to think of it, those are the organs that helps us think, see, and enjoy sex. Fish food = good brain and heart food.