Questions relating to the study of fish.

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3
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2answers
51 views

In practice, do fishes die from old age?

I was watching sea birds eating fishes and wondered if fishes actually died from old age, or if they are all eaten before this can happen? I reckon some big predator fishes must be able to live long ...
3
votes
2answers
57 views

How does a stonefish get oxygen out of water?

It is said that the stonefish (Synanceia) is able to stay out of the water for up to 24 hours. I wonder how they get oxygen from the air. Could someone explain this?
2
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1answer
37 views

Why does temperature shock kill fish?

As is advised with most fish you should avoid sudden changes in water temperature (for example by introducing new water that hasn't been left to come to room temperature). I have, however, never ...
-1
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1answer
58 views

Breathing under water

Why can fish breathe under water but land mammals can't? How can fish extract oxygen straight from water but humans can't?
3
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1answer
52 views

Identifying internal structures of dissected fish

Note : Images displayed below might be disturbing to some people. I have dissected a fish for the first time ! I have some idea of what some of the structures might be but I am not sure and so would ...
4
votes
2answers
70 views

Do swarms show intelligence?

Can you think of collective and swarm behaviors as "intelligence"? Would such a concept apply to a) ant colonies and b) fish swarms?
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1answer
43 views

Clownfishes and Sea anemones

Relation between clownfishes and sea anemones is a classic example of mutualism. I wanted to list the species of sea anemones that are involved in this mutualism but I got lost.. Could you help me ...
1
vote
1answer
26 views

What Freshwater Fish Are Affected By Magnetic Fields

I am interested in knowing which freshwater fish are affected by magnetic fields. I've heard that Lake Sturgeon are, but would like more references. This is for a project that will have buried 3 ...
1
vote
0answers
15 views

Good book for aquarium owning? [closed]

I'm looking for a good book on keeping a good ecosystem in a fish tank. This can include animals such as fish, crabs, turtles, etc. I want to know mainly how to start off as a beginner, so a ...
2
votes
1answer
58 views

observed luminescence in a piece of plaice

A plaice fish bought for human feed has been cleaned and cooked. Some parts of the raw body have been left out of the fridge at about 22°C for about 15 hours. During the following night a ...
5
votes
1answer
39 views

Why is clownfish attracted to actinia?

I heard that Actinia Equina normally eats what it can catch, but this clownfish here doesn't care much about that: https://www.youtube.com/watch?v=Ughm4mnZ1ls Since the actinia obviously can't hold ...
4
votes
1answer
258 views

How do sharks and other fish conserve and gain water in marine environments?

With the osmolarity of the average vertebrate being around 300mOsml, and salt water having an osmolarity of 1000mOsml, why does the water from the shark not leave to the salt water around it? I ...
1
vote
1answer
31 views

Did the Swedish cod fishery expand in the past years?

The Marine Stewardship Council states that the cod fishery in the Eastern Baltic sea recovered well and issued it's MSC certificate to the Swedish cod fishery in 2011 for that region. (MSC 2011) Data ...
4
votes
1answer
261 views

Are there predators evolved to eat puffer fish?

Puffer fish is known for having a anti-predation defense mechanism of having toxin-exuding spikes. Are there predators which evolved specifically to prey on puffer fish? (presumably, by evolving ...
2
votes
1answer
23 views

Effect of Ethanol on Brain Volume Measurements

I want to compare the brain sizes of two populations of fish. However, all the samples I have were fixed in 95% ethanol. As far as I know, 4% formalin is the normal fixative for soft tissues. Can I ...
5
votes
1answer
148 views

Tuna fish in Baltic sea?

Yesterday my grandmother ate fresh tuna at a friend's party. She swears it was fresh and bought at a local fish-shop. The problem is, that we live in Gdańsk, by the south-eastern side of the Baltic ...
10
votes
1answer
1k views

Do fish break a water molecule to absorb oxygen?

How do fish separate oxygen from H20 & consume it? Do they break the water molecule and absorb the oxygen only?
3
votes
2answers
65 views

Is vision a vestigial sense for deep ocean species?

Sunlight doesn't penetrate beyond a couple of hundred feet from the surface of the ocean. Species that exist at greater depth probably live in a state of perpetual night; yet from a quick google image ...
11
votes
1answer
187 views

Salmon returning to lay eggs

To spawn, salmon return to the river in which they were born. Is it because the individuals remember the specific river, or because populations are genetically conditioned to follow specific ...
6
votes
1answer
44 views

harvesting fertilized eggs from Tetraodontidae species?

I would like to know how easy/difficult it is to harvest fertilized eggs from Tetraodontidae species such as Tetraodon nigroviridis or Takifugu rubripes compared to zebrafish? Ultimately, I would like ...
11
votes
2answers
355 views

Why is there a difference in the rotation of the tail fin in fish compared to marine mammals?

I've been thinking about this one, but I can't seem to find what causes this difference. All fishes that I've seen have their tail fin positioned vertical: But all the marine mammals I know have ...
13
votes
1answer
237 views

Do the majority of fish lack scales on their heads?

Based on pictures, it seems to me that a vast majority of fish species that have scales do NOT have scales on their heads. Is that fact true? To make this properly answerable: lets' define a ...