Questions tagged [ichthyology]

Questions relating to the study of fish or icthyology.

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-2 votes
1 answer
27 views

Can a school of 'suction cup' fish block the gills of a predator as a defence mechanism?

(This is about a FICTIONAL FISH - I MADE UP THE FISH. To my knowledge, this concept is not based on any real principles or precedents.) Now, this fish has a strong capability for suction, and very ...
-4 votes
2 answers
198 views

Why can't fish extract oxygen from air?

I've read many posts here and elsewhere for example: Wikipedia where breathing is well described, but does not answer the question (or anything close.)# Wikipedia Gills, more specific, but still ...
0 votes
1 answer
96 views

How often do birds steal from fish traps?

Does anyone have any solid information about how often birds (e.g. cormorants, mergansers, gulls etc) steal fish from any sort of fish trap? Fish traps include, but are not limited to, fyke nets, ...
18 votes
1 answer
3k views

Male and female seahorses: which is which

Seahorses have two sexes. One has mobile gametes, the other gives live birth. I imagine that a biologist who discovered the seahorse would initially call the first "male" and the second &...
1 vote
1 answer
209 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 ...
1 vote
1 answer
32 views

Is there a database for fossilized coral reefs that have been reported?

Given that coral lives only up to 5,000 years, and I assume marine biologists have maps of where all known living reefs are around the world for research and monitoring, where can I find information ...
2 votes
0 answers
118 views

Identifying fish or shark jaw bone

I found this on the beach of coastal southern Maine in early March. The teeth are not a single row and lighter is for size comparison
7 votes
2 answers
7k views

Do fishes die from old age?

I was watching sea birds eating fishes and wondered whether any fishes died from old age or whether they are all eaten before this can happen? I imagine that some big predator fishes must be able to ...
8 votes
2 answers
1k views

Are tuna fish present in the Baltic sea?

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

Can a broken Swordfish's bill bone regrow?

The Broadbill Swordfish (Xiphias gladius) is characterized by a long bill or a "sword" which is an extension of its upper lip bone. The swordfish uses its sword in fighting, including ...
2 votes
2 answers
876 views

What drives male fish to spray their milt?

In mammals the sexdrive of the males is because the intercourse provides a satisfaction where after, the sperm is ejaculated into the female. However, the male sperm doesn't enter the female fish but ...
8 votes
1 answer
214 views

Identification of a strange skull

My father is a fisherman in the Baltic sea, and he has found this very strange skull. I would like to know to which animal it belonged. Can someone help identify it?
0 votes
0 answers
23 views

How do atherinidae survive the drought?

I found isolated pools in which there are Atherinidae, through the pebbly shores of Piave River (North-East Italy, Europe - in attachment there is a picture of the remainder of shores, after the ...
3 votes
0 answers
107 views

How does Anabantoideis' labyrinth function? What does it look like?

Anabantoideis are fish with an organ that allows them to take oxygen directly from the air outside of water. However, I cannot find much on how this functions, nor can I find any clear image of what ...
0 votes
0 answers
55 views

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 ...
1 vote
1 answer
71 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?...
12 votes
1 answer
278 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 ...
5 votes
2 answers
16k views

What are fish seeds?

I stumbled upon this term in a section called Induced breeding of Carps in an Applied Zoogy book. Traditional practice is to collect seed from the natural riverine habitatwhich also contain ...
2 votes
4 answers
177 views

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 ...
3 votes
1 answer
214 views

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 ...
4 votes
3 answers
450 views

How do fish communicate?

Fish, as far as I know (of course there may be exceptions), don't have any vocal organs, despite the fact they are proven to be social. So how do they manage to communicate with each other? On land, ...
5 votes
1 answer
172 views

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?
4 votes
1 answer
85 views

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?
3 votes
1 answer
127 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 ...
17 votes
2 answers
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?
5 votes
2 answers
9k 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 ...
1 vote
0 answers
37 views

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 ...
2 votes
0 answers
38 views

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 ...
2 votes
2 answers
120 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 ...
4 votes
1 answer
56 views

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?
-1 votes
2 answers
100 views

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 ...
2 votes
1 answer
75 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 ...
2 votes
0 answers
58 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, ...
5 votes
2 answers
205 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 ...
2 votes
0 answers
81 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 ...
2 votes
2 answers
2k 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=...
11 votes
2 answers
224 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 ...
-1 votes
1 answer
69 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
-1 votes
1 answer
87 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.
4 votes
1 answer
232 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 ...
1 vote
0 answers
33 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?
1 vote
1 answer
117 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 ...
0 votes
0 answers
130 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 ...
0 votes
1 answer
3k 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,...
3 votes
1 answer
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 ...
-1 votes
1 answer
99 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 ...
40 votes
4 answers
15k 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 votes
1 answer
24k 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 ...
1 vote
0 answers
7 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?