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I am quite aware that when you add salt to the water, it would stop it from freezing or drop below the boiling point. The ocean is salt water. I had thought that perhaps if I added salt, I could introduce marine fishes with my oscar I have in there. Before I consider it, does the salt harm the oscar? I believe there is the same concept of compatibility in terms of the aggression whether its freshwater or marine. What do you think?

McCollum

Keep fresh water fish in fresh water. Keep saltwater fish in saltwater. Most fresh fish can adapt to a little salt, and most salt fish can adapt to less saline conditions, but these extremes generally do not overlap. There's no "happy medium" where oscars can cohabitate with tangs. Just not gunna happen. For that reason there's been no observations on compatibility between oscars and SW fish. Not a great idea to pursue. If you have any more notions of delving into SW you need to read a lot of posts around the web, read a book, AND maybe talk to your LFS. That's not an either/or option. Multiple sources should be considered before buying anything.

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Critical Fertilator: The Micromanager of Macronutrients

I thought I am talking about regular salt as to add to water. I believe you are talking about the ocean salt then where it comes naturally. I believe in my knowledge as far as I know, agreeably there has been no evidence in terms of compatibility.

McCollum

An oscar will not survive the salinity that saltwater fish need and saltwater fish will not survive in the low salt level oscars. Generally even when salt is added to freshwater the salinity doesn't go beyond 1.005sg or the fish start to suffer bad effects. Some would argue even smaller amounts than that are bad and most do not add any salt to their freshwater tanks except temporarily to treat illness. Now minimum saltwater levels are considered 1.020sg and most marine tanks are kept closer to 1.025. We're looking at 5times the maximum salt level freshwater fish are suppose to be kept at. 1 fish or the other is going to end up dead. I've had trouble even finding plants, shrimp, and fish that can adjust to my brackish water tank which is halfway in between fresh and true marine. There aren't alot of brackish critters sold and even fewer that live in the exact same salinity. Trying to do it with a true freshwater fish and a true saltwater fish is just not going to work.

Im sorry marisun its not going to work. That kind of school science class stardard chemistry knowledge should never be applied to fishkeeping ,where a life hangs in the balance. If you tried it, youd kill your fish, end of story.

I forgot one part about it then. It must be about the PH, nitrogen level and chemistry that fishes could tolerate then. Good idea then Sorry,science was never my best subject.

McCollum

I forgot one part about it then. It must be about the PH, nitrogen level and chemistry that fishes could tolerate then.

No it's the salt level. Freshwater fish don't survive salt. That's why they are called freshwater. Saltwater fish don't survive without salt. That's why they are called saltwater. It's really simple. No chemistry involved or complicated science needed.

Look up references on "The osmotic barrier" . Basically the upshot of it all is that fish from high salinity have adaptations in the gills, and the renal system to help them expel salt , and maintain a freshwater system inside their bodies, and freshwater fish do the reverse and spend a great deal of time retaining available salts. You put one fish in the others environment for a significant time and what you get is either a dehydrated, or swollen pulpy mess with massive renal failure. Fish that start off freshwater and end up marine or brackish go through immense physoinomical changes to enable them to cope, and often , as say red and sockeye salmon prove- theres often no going back. Only a few species in the world can freely traverse both salinities without having to dedicate most of their time to one or the other to recover normal renal function. 99 percent of all species have no hope in hell of being able to replicate that adaptability, and even if they could it would take thousands of years for the adaptation to be completely stable.

If you think of it in simplistic human terms and its impact on the liver, its like someone who drinks only water taking to the "all vodka" diet. The liver and kidneys simply wont cope with the demands. Just as we cant drink saltwater indefinately neither can a freshwater fish. In fact we actually have more chance of being able to drink saltwater for longer periods than a fish can be in the wrong environment, because as far as body types go, we are generally less permeable in the external tissues,and more complex tissue and fluid barriers seperating different organs internally.

It is the thousands of years of develompent of these salt controlling organs that means you cant just up and mix fish from different salinities. I can see how you might think its viable from looking at hereditary lines, certainly cichlids and tilapia are found in varying salinities, and some are related to certain marine fish loosely speaking, but in your lifetime, even if you dedicated yourself to selective breeding you would not get an oscar to live in saltwater. Perhaps your childrens , childrens, childrens, chuldrens, childrens, children night manage. Even then, the death rates of the fish would still be fairly horrific. Personally id hold off until you have a few aquatic sciences phd's under your belt, then review how viable the project would be, and see if there was a single use for it worth the deaths of the thousands of fish it would take to try.

Nice post Git, that was what I didn't want to type out. We learned about osmotic barriers and effects and coping mechanisms in physiology this semester. Needless to say it just doesn't work.

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Critical Fertilator: The Micromanager of Macronutrients