# freshwater jellyfish??



## fishfreaks (Jan 19, 2005)

have you ever heard of or saw these creatures? my bf read that they exist in a magazine, but that was all they told, and now he wants to find one.


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## shev (Jan 18, 2005)

true jellyfish are marine organisms. but yes there are Fw jelly fish, ive never seen them in the home aquarium tho.

funny you should ask, i had just asked my bio teacher the same thing when we went over the cnidarians and stuff.

try googling craspedacusta sowerbii.


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## maxpayne_lhp (Jan 19, 2005)

I did! I've seen it on Discovery Channel! It was great, just look like a normal salfwater jelly fish! Hmmm but I dun remember where  sorry!...


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## shev (Jan 18, 2005)

almost just like them, they feed on zooplankton so they would be kinda hard to feed.


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## maxpayne_lhp (Jan 19, 2005)

Well, on the aspect of evaluation, do you have any idea?


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## Lexus (Jan 19, 2005)

http://nsm1.nsm.iup.edu/tpeard/jellyfish.html

http://www.microscopy-uk.org.uk/mag/artnov99/fwjelly.html

http://www.garf.org/freshjelly.html


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## fishfreaks (Jan 19, 2005)

wow, that was a super fast response, thanks guys!


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## shev (Jan 18, 2005)

> Well, on the aspect of evaluation, do you have any idea?


what do you mean? they musta stemmed off of true jellyfish from the sea.


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## maxpayne_lhp (Jan 19, 2005)

Or vice versa? I mean from where to where? The appear in the marine environtment first or the freshwater first? There must be some movement...


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## TheOldSalt (Jan 28, 2005)

I haven't looked at any of the links above, but I think I know the jellies to which they refer. In their case, a saltwater channel got cut off from the sea and slowly diluted by many centuries of rainwater, which means there was no movement at all.


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## MyraVan (Jan 19, 2005)

If you read this:
http://nsm1.nsm.iup.edu/tpeard/thing.htm
you'll find out that these things aren't true jellyfish; they didn't evolve from marine jellyfish. They are more closely related to hydras than marine jellyfish. It's one example of convergent evolution, where things that live in similar environments may look very similar, although they aren't closely related.


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## Osiris (Jan 18, 2005)

I would have to go with "theoldsalt" makes more sense. But who knows. 

I kept thinking, that this whole polar ice caps melting thing, would kill off marine life, as they are FW and the sea SG levels would significalty change if they all melted killing most marine life, but if done slowly like they are, they become adaptive to their enviroment...hmmm


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## Fishfirst (Jan 24, 2005)

what myravan is talking about is very accurate, a lot of species didn't evolve the same way in fresh water as they did in saltwater... but got similar results.


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## Guest (Mar 10, 2005)

id have to say that either side could be accurate. freshwater stingrays were developed the way oldsalt refers to, but some animals may looks like another but are completely unrelated.


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## TheOldSalt (Jan 28, 2005)

Yes, quite right.
Form follows function, after all, and a great many of the organisms on this planet may look very similar while not being even distantly related.

Adaptive evolution is a tricky process. It can only happen very slowly, of course, but it has to happen quickly enough to allow for the survival of the species.
For example, the polar icebergs are literally crawling with oodles and oodles of very colorful and fascinating small creatures. unfortunately, they have proven most difficult to study, for a temperature variance of only 2 or 3 degrees F will KILL them. THAT's specialization. While global warming may be slow enough to allow for many other species to adapt, these little critters will likey die. By the way, it has been postulated, rather credibly, that about 25% of the earth's species will be extinct within 50 years. Amazing, eh?

Passionflowers have evolved significantly just in the last 150 years or so. It was in response to the arrival of a new butterfly to it's range, the caterpillars of which found passionflower leaves very tasty. It is a fascinating story, and also very creepy, for the only logical explanation for it simply makes no sense. The evolutionary battle between these two species has been measurable at many points in the past century.

There is also a moth which has changed it's coloration to enable it to hide against the bark of trees which have been changed in color by pollution.

The point is that evolution can occur with surprising swiftness sometimes, but it usually doesn't.
There are of course those who insist that evolution does not exist, but evidence to the contrary is pretty overwhelming. Besides, would God have gone to all the trouble to create the lifeforms of earth, a monumental task, no doubt, only to fail to give them a way to survive the inevitable changes they would face? I think He's smarter than that. Besides, He probably gets a kick out of seeing what happens to them, I would think.

Please don't let this thread degrade into yet another religious debate.

Anyway, back to jellyfish. Yes, they live in saltwater mostly, but also brackish, and even in at least one freshwater lake in the indo-pacific. There are also some hydroids which resemble jellies, but aren't.


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## fish_doc (Jan 31, 2005)

I just read a article last week on how there are some places that have developed through time freshwater fish that are the same as their saltwater counterparts. They have conditioned them through generations by changing the water mix every generation. Now they are to the point where they are going to release them to the public for their freshwater tanks.

In my mind this is a nightmare. Now people will think they can buy any fish and throw them in any tank.


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## TheOldSalt (Jan 28, 2005)

Yep, that's big trouble waiting to happen if it catches on. I have a feeling that they won't be able to produce enough specimens to have a significant impact on the hobby as a whole, but I shudder to think what may happen if they do.

Do any of you remember a product a few years ago called "Magic Ocean?" This was a concoction used instead of salt which allowed the keeping of fresh and saltwater fish in the same tank. Yes, it really worked. What a mess it caused for a little while before it was finally removed from the market. Fish that couldn't understand each other, carrying diseases alien to each other, were being housed in the same tanks in some wholesalers facilities in the name of convenience. What it actually led to was catastrophe. It was a nifty little product for demonstrating osmotic pressure and such, but it's a good thing it finally died a quiet death.

Now we might have freshwater tangs and damsels and wrasses, eh? OY! A lot of hucksters are going to rip off a lot of people soon.

Are you guys aware of a French company with a name which translates as "Aquafish?" These guys specialize in raising the fry of species normally impossible to keep in aquaria due to strict, specialized food requirements. By denying the fish any access to their special food of choice during their development, the fish are forced to remain unspecialized feeders. This is just fine and dandy in that it finally lets us keep things like Meyeri and Ornate Butterflyfishes, but it also leads to people getting the wrong idea about the needs of these species. Ripoffs aside, the availability of keep-able specimens can only lead to an increase in demand for those species, specially-raised or not.

Nothing but trouble.


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## fish_doc (Jan 31, 2005)

I found the article in the magazine and read it again. It is being done by a company named marical. It sounds like the suppliment the food and water with certain minerals. Sounds like a reliving of the product you previously mentioned.


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