Questions tagged [ichthyology]

Questions relating to the study of fish or icthyology.

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Why and who: named some fish "bashers" (African electrofish taxon "stonebasher")

Folklore question for itinerant elephantfish/electrofish experts happening to see this:Is any stonebasher fish named for a behavior related to bashing... something or some part of its anatomy against ...
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1 vote
1 answer
41 views

Fresh Water Fish Identification

A couple of days ago I just adopted a group of 7 fishes, 2 inches long each, orange-pinkish color, a black dot before the tail, very fast, active and peacefull. Looks like a kind of tetra fish. Anyone?...
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1 answer
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Where to find morphometric data for fish?

I need data regarding the aspect ratio for caudal fins of different Elasmobranchii. It should be some easily retrievable information but apparently fishbase doesn't have this type of data for many ...
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3 votes
4 answers
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Do schooling fish make sounds that predators could detect?

Do schooling fish make sounds, voluntarily or involuntarily? A general internet search for "schooling fish sounds" doesn't provide many answers, but I found a paper from 1960 describing ...
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1 answer
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What are these animals, and what happened here?

While walking along the northern shore of Lake Ontario, I noticed the following strange scene: Here is a closer angle: What are these animals, and what is the likeliest cause of this?
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4 votes
1 answer
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Is the fin of ray-finned fish live tissue or more similar to scales?

In ray-finned fishes, are what exactly are the fins made of? Is it modified skin, dead tissue like scale or nail on humans, or something completely different? Can the fin heal?
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In this aquponic tank, what are these three plants and could they be killing my beta fish?

I have a small aquaponic fish tank. In the tank there are two unknown types of water plants from a local pet store and the top there are three air plants from a local garden center. This tank was ...
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Are there taxonomic keys for members of the family poeciliidae in America?

I wish to know what are the taxonomic aspects necessary for the identification of certain species of poecilids, specifically what is the role in the counting of rays and spines and also the ...
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Is white fish + liver nutritionally equivalent to oily fish?

UK government nutrition guidelines say: Aim for at least two portions (2 x 140g) of fish a week, including a portion of oily fish My understanding is that the main difference between oily and white ...
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4 votes
1 answer
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What is a lamprey's tongue derived from?

Tetrapods have tongues derived from the 2nd gill arch and nearby muscles. Lampreys are not tetrapods, and lack jaws, yet they have a tongue. What structure was this tongue adapted from?
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3 votes
1 answer
120 views

Can anyone identify this fish?

I saw it in the sea very close to the beach in front of Starfish Hotel in St Lucia. It had some spines along its back and it seemingly had fins on each side that split open into 4. It used its front ...
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-1 votes
2 answers
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Could the problem of overfishing be solved by throwing fertilized fish eggs at the right place and deepness into the sea? [closed]

I hear sometimes about over fishing and I wonder if the following idea could help to solve the problem. My idea is to throw fertilized fish eggs at the right place and deepness into the sea. These ...
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2 votes
1 answer
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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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5 votes
2 answers
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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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2 answers
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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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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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1 answer
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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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4 votes
1 answer
105 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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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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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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1 answer
902 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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3 votes
1 answer
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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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-1 votes
1 answer
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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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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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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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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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3 votes
1 answer
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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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3 votes
1 answer
33 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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9 votes
1 answer
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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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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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7 votes
2 answers
169 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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1 answer
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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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40 votes
4 answers
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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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3 votes
1 answer
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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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2 votes
1 answer
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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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2 votes
1 answer
166 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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0 votes
1 answer
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what is the name of this fish?

]2 fishes are of length 2 to 3 inches.
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24 votes
2 answers
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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8 votes
1 answer
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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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3 votes
1 answer
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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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2 votes
0 answers
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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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1 vote
1 answer
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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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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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4 votes
1 answer
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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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2 votes
1 answer
110 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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1 vote
0 answers
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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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