Questions tagged [ichthyology]

Questions relating to the study of fish or icthyology.

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2
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0answers
37 views

Is it true that oxygen levels in water limits fish size?

This answer says that breathing water is inefficient, and that may act as a limiter to the size of fish. I've heard this in a couple of other places as well, but cannot recall the sources. However, ...
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18 views

Taxonomy and morphology of marine fish

is there a relationship between taxonomy and the presence of stomach in marine fish? In other words, are stomachless fish present in only certain phylogenies or are stomachless fish scattered ...
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2answers
75 views

Are there adaptations in tropical fish to compensate for less oxygen in water?

Warmer water means that the amount of gases- especially oxygen- dissolved in it reduces, since solubility of gases in a solution in most cases decrease with an increase in temperature. I'm interested ...
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0answers
72 views

How do schools of fish get enough oxygen?

Fish get oxygen from the water running over their gills, during which up to ~80% of oxygen is removed from the water. In schools of fish, how do fish swimming behind other fish get enough oxygen in ...
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1answer
47 views

Is amphibians being descended from fish reflected in the animalia taxonomy?

I think it is common knowledge that amphibians are descended from fish. At some point there was a transition from sea to land. But when I try to confirm this through the Animalia taxonomy, the ...
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2answers
83 views

How many Watt-hours can an electric eel produce in a day?

Electric eels are cited as being about to produce about 860 watts of energy. But I haven't been able to find information on how long they can sustain their charge. https://www.youtube.com/watch?v=...
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2answers
178 views

Can a shark stall?

Today in marine biology I learned that, like airplanes, sharks use their pectoral fins to generate lift. The question that neither me or my Professor know is if a shark can or cannot stall. A ...
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18 views

Pectoral fins in fish, why the terminology abductor and adductor for main muscle groups?

Fish pectoral fins are roughly divided into large dorsal muscle mass, and a large ventral muscle mass. Just from that division and position of muscles, the ventral muscle mass seems to mainly lower ...
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1answer
44 views

How do fish transport egg to, and out of, coelom?

How do gametes get into coelom, and, later out of it? Excretion can be under quite heavy pressure, see https://www.youtube.com/watch?v=1OsRbuEINXI
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1answer
80 views

What fish is it?

I bought this 2 weeks ago, but i forgot to ask the seller, what fish is it. Currently the size is 1 inch.
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1answer
51 views

Can the extinct Chinese Paddlefish be revived?

I learned that a rare and unique giant Chinese Paddlefish recently became extinct. I'm wondering if samples of DNA were collected by scientists to allow reviving of the specie in the future. My quick ...
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26 views

Why are lungfish cartilaginous?

Lungfish have a cartilaginous notochord, and a reduced cartilaginous skull. Is this feature to improve flexibility, or is there another reason?
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1answer
112 views

Can an Ichthyologist identify this Canadian freshwater fish?

This will be very simple for a lot of you! But I been getting mixed answers about his catch. Is this a chinook salmon or brown spotted trout? Caught in Angus, Ontario, Canada. (Hwy 90 Bridge) I ...
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16 views

With so many different species of fish with often very minor differences, how is the precise species identified authoritatively?

While it seems to me that common mammal species are usually distinct enough that there isn't much trouble in accurately defining and identifying a specific species, for example of a deer, I see that ...
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36 views

How do fish persist in the upper parts of mountainous rivers with waterfalls?

I was recently traveling in a remote mountain region and hiking alongside a very small river. What caught my attention was the fish in the small ponds under the waterfalls. These ponds were just a ...
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13 views

How do I calculate amount of nutrients retained/excreted in fish?

In preparation for my exam in fisheries and aquaculture, I looked through last years exam (with an answer sheet) and stumbled upon this multiple-choice question that I can't figure out how to solve. ...
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1answer
56 views

What is the very hard sphere inside the eye of many common fish made of and how is it called?

Inside the eye of many common fish, like tuna, scad, snapper, actually probably all fish I have eaten, is a small sphere made of some very tough substance. This sphere is even hard to crush with teeth,...
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1answer
1k views

What fish is this?

I was out snorkeling at Biscayne Bay in Miami, Florida in the shallow waters near the shore when I saw this fish. What fish is this? I see it has black spots at the bottom and five white lines along ...
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1answer
28 views

How to calculate water pressure (Kpa/Mpa/PSI) with depth in the Biofloc fish farming?

Can you tell us a little bit about the water pressure (Kpa/Mpa/PSI) with depth in the Biofloc fish farming and the calculation of Kpa ​​/ PSI / Mpa so that one can understand which air pump machine ...
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0answers
9 views

Regalecus glesne or Regalecus russelii?

I was doing research on Regalecidae, and I came across an online database. Here, on the database, there are 12 matches for Regalecus russelii. At the bottom of most of these pages, there is a related ...
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4answers
12k views

Can a person survive on blood in place of water?

This question: Can you get enough water by eating only fish? asks if a person could survive on fish alone. Can a person survive on fish and/ or blood alone of any species if stuck at sea or animal ...
4
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1answer
20k views

Can prawns be classified as fish, or is their position ambiguous?

Today a zoologist told me that prawns and fish are very similar, but zoologists/taxonomists have put them in different categories because their distinction is unclear (like hydrogen in the periodic ...
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0answers
6 views

What external signals do tell catadromous fish to go from the sea to the rivers?

What signals do tell catadromous fish to go from the sea to the rivers? Is it photoperiodicity? Are there any other signals?
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2answers
181 views

Any idea what this fish is?

Bought this Fish at the pet shop today. Forgot it's name. That pink fish
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2answers
159 views

Never caught this fish before

After catching a bunch of mangrove snapper using live shrimp, my son caught this fish in about a foot of brackish saltwater water off a dock near a rock wall in Vero Beach at around 10:00 AM on July ...
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2answers
3k views

What exactly is this small puffer fish doing and how did it manage to accomplish such a feat?

I recently saw a video on youtube where it shows a puffer fish making intricate designs in the sand: OZZY MAN VIDEO The puffer fish made this design on the sand: What exactly is the puffer ...
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3answers
5k views

What is the difference between the evolution of fins in whales and fish?

For a homework assignment I received the following question: Which statement best explains the evolution of fins in whales and fish? a. The common ancestor of whales and fish possessed genes for ...
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0answers
89 views

What kinds of fish tend to have a rapid death after being caught?

I am asking this question because I am trying to make my diet less cruelty-oriented, for this reason this question can be related to trolley problem since I am coping with an ethical problem trying to ...
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0answers
82 views

Is it humane to kill fish by immersing them in very cold water or ice slurry?

I'm doing some research and advocacy for the humane treatment of wild-caught fish. Humane standards are more common on fish farms than at sea, so I am trying to identify some reasonable standards for ...
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1answer
151 views

What kind of fish is this white blue-stained fish?

This fish has been spotted at the Great Barrier Reef near Cairns (Queensland). I put a big effort to find it via Google but never could encounter anything similar. I have also made an attempt to find ...
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1answer
2k views

How long do fishes survive in a milk environment?

Suppose you placed a fish, a goldfish for example, into milk instead of water. How long could you expect the fish to survive? Would it die due to lack of oxygen? Is there any other factor that could ...
4
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1answer
6k 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 ...
3
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1answer
41 views

Is there an adhesive that could used for larval fish?

I am currently working on an experimental design that requires a larval fish (~ 4mm long) to be affixed on a metal wire tip on its dorsal side. Now, I was thinking of a glue or adhesive to do the job, ...
3
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1answer
31 views

Which fishes produce alarm signals to warn other group members about in coming predators

Atlantic Goliath Groupers are fishes which produce unique low frequency sounds to mate and when approached by predatory fish . The sounds produced when approached by a predator (or even a scuba diver) ...
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41 views

DNA like marine animal or egg

What is the name of the marine egg or living being that is transparent like a jelly fish or a Venus girdle, with a shape like a DNA or better like a chain of infinites, long as half of a hand and ...
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1answer
37 views

Difference between Sphyraena obtusata and Sphyraena novaehollandiae

"Striped barracuda" is the common name for both Sphyraena obtusata and the Sphyraena novaehollandiae. Here's links to both fish species from fishesofausralia.net: S. novaehollandiae and S. obtusata ...
2
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1answer
85 views

What are the teeth of the viperfish composed of?

One of the viperfish's (genus Chauliodus) most unique traits is the transparent, needle-like teeth. Some other abyssopelagic fish (e.g. certain angler fish) have similar teeth. I'm curious as to what ...
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0answers
68 views

What type of fish is this

I saw this fish in an aquarium in a nearby house .I am not sure which species and sex this fish belongs to. [![enter image description here][1]][1] [1]: https://i.stack.imgur.com/oOAZx.jpg
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2answers
203 views

Why do fishes have both a gustatory and an olfactory system?

I would like to know if there is a reason why fishes (and many aquatic species) have both an olfactory and a gustatory system. As far as I know, in all fish species the chemoreceptors, organs and ...
6
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2answers
5k 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 ...
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1answer
75 views

What ecological niche do disk shaped fish exploit?

I looked up "Early Triassic" to get a sense of what that meant and I ended up on this image of marine life at the time. I noticed some disk shaped fish (#8 in the picture: Bobasatrania (durophagous ...
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1answer
184 views

Do Osteichthyes fishes have any cartilage?

Higher vertebrates, such as mammals, birds, reptiles and amphibians have both bone and cartilage. But do Osteichthyes fish (Bony fish) have any cartilage? Or do they only have bones? I've searched ...
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1answer
45 views

What kind bottom feeder is this?

It’s about 2 1/2 inches long and had a little tail on the end. Also has short feelers that almost look like a moles.
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1answer
198 views

What kind of fish is on the picture?

I saw these fish in a video at an art exhibition, I'd like to find out what kind they are.
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1answer
204 views

What type of fish is this and why is it so big?

This is a screenshot from a youtube video that you can watch here: https://www.youtube.com/watch?v=zcdJNPYkIE0
3
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1answer
31 views

Formula for Oxygen Consumption for Atlantic Salmon (Mathematical) - insecurities regarding variable

The oxygen is calculated in mg per kg per something, so what does $h^{-1}$ stand for? hours maybe? The formula given below is an estimation of oxygen consumption for Atlantic salmon \begin{...
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2answers
1k views

A weird-looking fish with a shield

I found this photo in a local news page. The page claims that this fish is a new species that was found by a Malaysian fisherman. Is this true or is it a known fish and already has a name?
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1answer
82 views

Cichlid fish in Africa

Are the cichlid fish in Africa an example of divergent or convergent evolution? On the one hand they have evolved similar features to each other indicating convergent evolution, but on the other, they ...
2
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1answer
50 views

Does the yolk sac for Danio rerio form at the vegetal pole?

Does the yolk sac in general form always at the vegetal pole? If so, is this the case for Danio rerio (the zebrafish)?
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1answer
156 views

What the name of this fish?

Well saw this on a fish group on facebook. Noone can give a decent answer so I came to you guys hoping you can help us? The one who posted lives in the Philippines and he said he caught it in the ...