Questions tagged [ichthyology]

Questions relating to the study of fish or icthyology.

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CO2 injection into a Planted Aquarium - detriment to Fish? [migrated]

From the start, thank you for your time and consideration. Whilst planning a planted aquarium setup that would include CO2 injection, I stumbled across an article about possible behavioral ...
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1answer
55 views

What Old World fish produces “white gems” in its brain?

In his ancient list of "white gems," Isidore of Seville mentions the "cinaedia," which he describes as follows: Cinaedia is found in the brain of a fish with the same name; it is ...
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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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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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78 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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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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2answers
92 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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1answer
60 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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20 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
82 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
55 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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30 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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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
79 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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34 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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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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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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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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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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89 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
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, ...
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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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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
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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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
161 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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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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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 ...
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1answer
32 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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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
158 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 ...
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1answer
44 views

what is the name of this fish?

]2 fishes are of length 2 to 3 inches.
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4k 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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1answer
960 views

What sort of fish is this?

Just saw a meme online with this fish on it. Is this a real fish? Can some aquatic expert identify this for us?
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1answer
69 views

Is the deep ocean fish look ugly because due to darkness there is no visual sexual selection? [closed]

Is the deep ocean fish look ugly because due to darkness there is no visual sexual selection? If so, is there a common notion of beauty between humans and animals?
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75 views

Did the Broadbill Swordfish population fully recovered?

Regarding the Broadbill Swordfish Xiphias gladius: I read Richard Ellis "Swordfish: A Biography of the Ocean Gladiator", Chicago University Press, 2013. The chapter about industrial-strength fishing ...
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1answer
77 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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114 views

Could fish safely “breathe” pure oxygen in their water?

I've heard it said various times before that humans can't breathe pure oxygen, or at least not for very long, before it would kill us. But during a discussion on Worldbuilding, the difference between ...
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50 views

anyone can help identify this aquatic microganisms?

I extracted from fish excretion and at 400x At the moment i have yet to try any medication because i don’t know what this is. Can someone who has seen this before share the light? thanks!
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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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Who cleans the cleaner fish?

Cleaner fish are those fish that eat the dead skin cells and parasites off from other usually larger fish. ( such cleaners include wrasse, cichlids, catfish, shrimp etc ) I wondered if the cleaner ...
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1answer
146 views

Can anyone tell me what type of fish this is?

Notice the reflective patterns on its underside. I think it must be a deep water fish. It was found washed up on the ocean sand in Myrtle Beach, South Carolina (USA) after a hurricane.
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1answer
199 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
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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 ...
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331 views

Why don't fish get hurt with so many sharp fish bones?

Why don't fish get hurt with so many sharp fish bones? And why don't fish feel pain when they swim? Don't those sharp fish bones stick into the flesh while swimming?
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Devonian Fish Diversity--What Would it Have Looked Like?

For 70 million years, the oceans, lakes and rivers of the world teemed with seven groups of fish: Placodermi Acanthodii Agnatha Chondrichthyes Sarcopterygii Actinopterygii Now two of those ...
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What is the animal in this video?

I made some research however there seems to be a conflict with this animal's translation to my language and the original. So I couldn't find it. Do you mind helping me out ? https://static.59saniye....