Why do fish look black in huge tanks?

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Caincando1

Feeder Fish
MFK Member
Jul 14, 2006
35
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Rochester, MN
Why do fish always turn black or look black in HUGE tanks. Last weekend I stopped by the local nature center to check out there 1700 gallon tank full of natives. All the fish, no matter what species where all very black. I've noticed this same thing at the local Cabalas where they have an enormous indoor tank.
 
this is just a hypothosis but mabe the fish isnt really balck it just appears black throught the hugley thick glass or acrylic also even the smallest amount of inclarity when seen through a magnifier like glass and arcryllic (plus the larger volume of water between you and the fish) is comdensed possibly causing a darker look to the fish. just an idea, im sure someone will come along with a much better explaniation but thats what i think :)
 
Light moves through or bounces off different materials in different ways. light behaves like waves with direction, amplitude, reflection, color, and interference. So on large tanks with a Large boddy of water and thicker glass its harder for the light to get through. if you use a light sand and more lights it cures the problem. So grmanrocks was spot on
 
So the fish aren't really turning black they just appear black due to the thick glass? Makes sense. That's to bad cuz it makes the fish look crappy. Especially at Cabalas where the glass must be 4-6 inches thick.
 
That has nothing to do with the size of the tank (on the large side) nor the thickness of the glass, it depends on the water quality and how stressed the fish are. Fish are usually darker when they are scared or stressed, if the water parameters are not good the fish will not look as good, and then certain types of fish are simply dull looking when they get really old.

You can not base such a decision on two tanks that you saw.
 
Both tanks have NA natives. Most of which I've caught in the wild many times. All the speices are the same black color. Sun fish, bass, carp etc. are all really black in color and considerably darker than they are in the wild.

I'm just wondering why.
 
Both tanks have NA natives. Most of which I've caught in the wild many times. All the speices are the same black color. Sun fish, bass, carp etc. are all really black in color and considerably darker than they are in the wild.

I'm just wondering why.
That simply means they suck at keeping fish.
 
none of those places have lighting on the tanks... when you catch those fish it is mostly in the sunlight.
 
That has nothing to do with the size of the tank (on the large side) nor the thickness of the glass, it depends on the water quality and how stressed the fish are. Fish are usually darker when they are scared or stressed, if the water parameters are not good the fish will not look as good, and then certain types of fish are simply dull looking when they get really old.

You can not base such a decision on two tanks that you saw.


You are correct but light refraction comes into it as well hens you require bigger lights to penetrate a deeper depth also glass will refract light have a look at this web site.





http://www.reachoutmichigan.org/funexperiments/agesubject/lessons/ftoptics.html



I do agree with you but the tank size is a part of the equation.


If you want to make the fish brighter simple more light but then the plot thickens Too much light will not blind, or fry them, but they may hide out. Intense lighting in combination with high nutrients will enhance algae growth.
 
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