Transparent fish gives scientists clear view

Clear female zebrafish.

Scientists have created a transparent fish that lets them see through its skin to watch the progression of disease in real time.

The fish, a breed Zebrafish named Casper, has granted researchers further insight into how diseases, especially cancer, act in living organisms, not just in a test tube or a dissected animal.

"It's the difference between watching a video and just seeing a snapshot," said Richard White, a clinical fellow in the Stem Cell Program at Children's Hospital Boston.

White created the new breed of Zebrafish, described in the Feb. 7 issue of Cell Stem Cell, a journal. White said he can read a newspaper through the transparent fish and see its beating heart as well as other organs.

In one experiment, White transplanted melanoma, or skin cancer, into the belly area of the fish. The cancer cells grew and within five days began to spread to the skin.

"It's like the cells know where they want to go," said White, suggesting the cells have some kind of homing mechanism. Smith said he plans to study ways to disrupt the cell's ability to find and grow in a new location.

The fish also can provide insight into stem cell transplants. Oncologists use blood-forming stem cells to rebuild healthy blood, but not all transplants are successful and "take."

White showed that the process can be observed in the new Zebrafish. He irradiated the fish's bone morrow and then transplanted fluorescent stem cells from another Zebrafish. Researchers can now more closely study stem cell transplants.

White created the new breed by mating two existing breeds. He mated a fish that lacks black pigment with one that lacks reflective pigment. The result is a fish with only yellow pigment, which looks clear.

Betta splendens

The Siamese Fighting Fish (Betta Splendens) is a beautiful and hardy fish, which is becoming ever more popular as the correct and much better choice than the poor Goldfish (Kingyo) to be kept in small home aquariums. Contrary to Goldfish - which would grow to 25+ cm and live over 20 years if they weren't massacred by the thousands still as juveniles, due to being put in those totally inappropriate little bowls - the Betta grows to only 5-6 cm and lives only about 3-4 years, so even beginners and "casual aquarists" can easily keep one very well and for all of its natural lifespan.

However, Bettas suffer from a very common misconception about them, even among aquarium hobbyists: they're reputed (as the common name suggests) for being incredibly aggressive and must be kept isolated. This is NOT true! In general, females are quite peaceful, and males are only aggressive towards other males of the same species (they may even fight to death) and sometimes to fish that look like them, such as dwarf gouramies and paradise fish. Because of this aggression between males, and the fact that Bettas can breath directly from the air, they are kept in those tiny pots in pet shops. But just because they can survive in those pots doesn't mean they enjoy it. Like any other fish, Bettas will be much happier and healthier if they live in a tank which at least allows them to swim around a little. Breeders say that 2 liters is enough, after all, for those who own a lot of male Bettas it gets complicated to keep all of them separated in larger tanks. But for those who own just one Betta at home as a pet, it's a very small extra investment to give him a more comfortable life than his "breeding" cousins, and keep him in a decent tank (20+ liters).

In fact, they make excellent fish for peaceful community tanks, as long as it's well planted, good-sized tank and you keep just one male and/or any number of females. In the community tank, it's the Betta who usually suffers from the harassment of other more active species, such as tiger barbs, zebra danios, serpae tetras and others, who can tear off his long fins and force him to cower in a corner, even kill him. He also becomes an easy snack for fish large enough to gulp him into their mouths, since he's a slow swimmer, so I emphasize that he's good only for very peaceful communities. I've personally kept them in 200-300 L planted community tanks, where they lived for years and even made bubble nests and bred in there. Obviously, the fry didn't survive and ended up as live food for the other fish, despite the valiant effort of the male to try defending them.

Acanthuridae

Acanthuridae ("thorn tail") is the family of surgeonfishes, tangs, and unicornfishes. The family includes about 80 species in six genera, all of which are marine fish living in tropical seas, usually around coral reefs. Many of the species are brightly colored and extremely popular for aquaria.

The distinctive characteristic of the family is a pair of spines, one on either side of the tail, which are dangerously sharp. Both the dorsal and anal fins are large, extending for most of the length of the body. The small mouths have a single row of teeth used for grazing on algae.^[1]

Most species are small, ranging up to 30 cm, but the whitemargin unicornfish Naso annulatus can reach a meter in length. These fish can grow quickly in aquariums so it is advisable to check the average growth size and suitability before adding to a marine aquarium.

Yellow tang

The yellow tang (Zebrasoma flavescens), also called Pacific tang, is a saltwater fish species of the family Acanthuridae. It is one of the most popular aquarium fish.

Acanthurus triostegus

The manini (Acanthurus triostegus) is a small surgeonfish about 5 inches long. It is yellow with black stripes on its side like a zebra. Its resemblance to a prisoner’s uniform gave it the nicknames of convict surgeonfish and convict tang. Manini is one of the favorite food fishes found everywhere in shallow waters around the islands of Samoa and the Hawaiian islands. Like alogo (Acanthurus lineatus), the manini belong to the family of surgeonfishes, because of their sharp blades by their tail fin. Even though they have this weapon, they do not use it much.

Manini often swim in huge schools of thousands. There are two reasons why they have such huge schools. First, It helps them escape predators. When a large fish attacks a school of manini, they scatter like an explosion. This move confuses the predator and the manini get away. Each manini then has another chance at life if they stay with the group. Second, the manini also use their schooling behavior for food. They like to feed on thin algae which is fiercely guarded by alogo and damselfishes. Just the sight of manini get the alogo fired up. A single manini would not even stand a chance against these predators but a group can succeed. When the alogo chases one manini, the rest of them eat the alogo’s garden of algae.

Mantis Shrimp

This highly intelligent hunter with claws can lash out at prey with the force of a gunshot. Larger varieties have been known to shatter glass or sever human fingers. Most are either “spearers” (with sharp, mantidlike claws) or “smashers” (with blunt, clublike claws for cracking hard-shelled prey). Rare among invertebrates are the monogamous mating habits that several species demonstrate. Mated pairs share a burrow, and the male hunts for both his mate and young.

Black Swallowe

The black swallower (Chiasmodon niger) is a deep sea fish that has the ability to extend its stomach 3 times its size so that it can swallow fish that are bigger than itself. It can be found in deep seas up to 1,500 meters or in hot tropical waters. It creates its own light because of the darkness found in some parts of the Pelagic zone. The black swallower can grow up to 25 centimeters.