Thermoclines

[drclifton]

I'm curious about temperature shock when transferring a fish to a new environment. Wouldn't a fish be subject to the same Thermoclines a diver experiences in the wild? So why do they react so poorly to slight, but abrupt temperature changes in the home aquaria?

 

[thegrun]

With a thermocline the fish can swim up or down to stay with temperatures they want, not so in out tanks. Most fish can survive rapid temperature swings but it is not ideal and coupled with the water chemistry changes they experience when being transferred reducing the temperature swing helps minimize the shock to their systems.

 

[davocean]

Agree, fish simply follow currents and water temps that suit their needs.
When we place them in our small systems we are subjecting them to a number of changes, and that can stress the fish

 

[Dkuhlmann]

Our tanks don't have thermoclines, and fish in the wild usually live above the thermocline because of lower oxygen below it. So I agree any abrupt changes in temp in our tanks or any fast change in any parameters fish and corals will act accordingly and those who can move to a more suitable spot will.

 

[Buzz1329]

Learned a new word/concept today. Thermoclines.

Thanks.

 

[wakesetter]

Have you guys that responded spent much time in tropical waters? While snorkeling or diving, you can cruise through temperature variations as much as 10 degrees in a few feet. There are some spots that we do both in Hawaii that have haloclines and thermoclines that are swirled through a bay. While following a fish, they generally cruise along in a straight line through multiple temperature and salinity variations and it has no effect on them. They don't bob and weave, looking to stay in one temperature or salinity zone. How do I know where there is a salinity variation? You can see it in the water. The upper water will be colder and blurry, go down 2-3 feet and its clear and much warmer. The bigger issue in the aquarium is that these variations are another stress factor that can contribute to disease so we try to minimize variations in order to maintain the most consistent environment we can, keeping the immune systems of the fish as strong as possible by decreasing their needs to compensate for variations. In the natural environment, the fish have less stress factors and can shake these fluctuations off much easier than in our aquariums.

Regarding the fish staying above the thermocline for more oxygen, warmer water holds less oxygen, so your comment doesn't really work. If oxygen was the concern for the fish, they would stay below the thermocline, where the cooler water would hold more oxygen and where their metabolism would be lower, using less oxygen.

not trying to come off as a know it all here, just trying to give the OP the best answer possible.

 

[Dkuhlmann]

Yes my statement works very well as I fish walleye tournament all over and when fishing in the summer I fish above the thermocline because there is dead water below it. Dead water as in dead plants due to very little oxygenThen after the fall turnover when the water basically flips the fish are all over from top to bottom and the dead plant life that was below is now on the surface and makes a huge stinking mess. You can even see the thermocline on any quality fish finder. So I can tell you without a doubt your theory is incorrect.

 

[wakesetter]

well that argument doesn't work at all. Fishing freshwater from the top of a boat doesn't give you much knowledge about a reef environment. You can't really compare freshwater and saltwater environments. You don't get rotting plant life lowering O2 levels in the reef, if you go to the bottom of a reef and dig around, not rotten stinky stuff. Just clean fresh sand. Show me a reef that turns over every fall, it doesn't happen. There is infinitely more water moving around and an infinitely larger body of water on a reef. Lakes are largely stagnant, allowing stuff to sit around and rot. I can tell you without a doubt that you are comparing apples to oranges. We are discussing the ocean, not a lake. Along with personal experience in the reef environment I also have a degree in Ecology and Systematic Biology with a concentration in Marine Environments, I'm not just making things up.

 

[Dkuhlmann]

I wasn't talking about a reef, I was talking about a thermocline and how it relates to just the thermocline. Reef's don't exist in a thermocline situation at all. Mostly because the water is too shallow. The same thing applies to fishing in the Gulf of Mexico the only difference is that the thermocline is much deeper. Some fish like the water difference at the thermocline and live close to it as its the only "structure" in that area.

Look I wasn't trying to argue with you I was simply stating what I know about thermoclines and in most reef locations the thermocline is non existent.

You're right reef's don't turn over every fall because there is no existing thermocline. A thermocline is the area where there is the greatest degree of different water temperatures exist. There are moderate changes by a few degrees from surface to substrate but most of those changes aren't a thermocline.

Oh and no lakes are not largely stagnant.

So once again reefs don't exist in areas of thermocline which is usually in much deeper water than most reefs exist.

I'm surprised you didn't learn more about thermoclines in your studies of Marine Environments.