An amazing discovery in the fish world ! !

We were taught when we were in chool that humans and animals are warm-blooded , and fish, reptiles and amphipians are cold-blooded creatures.
However, scientists have now made the amazing discovery that one kind of fish is actually warm-blooded !
This fish, called the Opah, or Moonfish, lives in the cold depths of the ocean. Most fish that live in that cold of water are very slow moving because they get so cold that their heart does not work right.
You might have seen this effect if you have goldfish, and the bowl got too cold during the winter and the fish could barely move. Then , when you put them in a warmer room; they warmed back up and started swimming around again.
The Opah swims by moving its fins very fast, which keeps the blood circulating faster and generates heat in the fish's body. They also have two sets of gills, so that the warmer blood can help heat up the cold blood from the gills and it enters the Opah's body at a warmer temperature.
They are pretty large fish; so we won't likely be having one in our aquariums soon; but just knowing that such a thing as a warm-blooded fish actually exists is pretty interesting.

http://www.smh.com.au/environment/animal...h259l.html

Opah is indeed the first fish species being discovered as full warm-blooded. I always thought it is strange how they do not freeze to death in such cold environment. Water absorbs heat from anything that is warmer than the water itself. Anything with body temperature higher than the water will continuously losing body heater rapidly when in the cold water. Anyway, I wish I am that immune to cold, so I can swim outdoor during the winter.

It is also true that most cold blood animals such as fish are depended on the temperature of their surroundings to "warm" themselves up in order to function normally.

No, you won't be able to have Opah in your home aquarium. It is not because the size issue, but rather due to the water pressure they are used to. Since Opah is living in deep ocean where the water pressure is extremely high, they will most likely die immediately once being put in shallow water.

It seems to me that since the Opah has to move its fins really, really fast to keep the blood circulating through its body and keep the fish warm, that it probably expends a lot of energy while doing this; just like we would do if we were in a cold place and trying to run or jump to keep warm. It is probably a very good thing that the Opah is fast enough to catch the unsuspecting and slower fish that it eats; because I would guess that it has a much higher caloric requirement than the semi-dormant fish have.

You would think that after all these years, and all of our modern day equipment; we would not still be finding these creatures that we did not even know existed, and even some that were thought to have become extinct millions of years ago have been discovered living in the depths of the ocean.

Even Panda bears were though to be a myth until well into the 1800's; so who knows what creatures we have yet to discover are real that we also thought were a legend and not truly existing.