Questions tagged [ichthyology]

Questions relating to the study of fish or icthyology.

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0answers
48 views

A fish with 3 paired fins

Many species of fish have 2 or 4 fins combined into pairs. But is there a fish with 3 (or even more) paired fins? Or has it ever existed in the past?
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1answer
123 views

If an organism is supported only by cartilage, does it have an endoskeleton?

Lamprey and sharks lack bones, but does this mean they are not classified as having an endoskelton? Does an organism need bone to be considered as having an endoskeleton?
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Does overfishing in one ocean hurt fishstock in another?

If there's overfishing in the Atlantic or North Sea - will this affect fish stocks in the Indian ocean? Are there papers on this? The question I'm trying to answer is whether overfishing by developed ...
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1answer
165 views

What type of jellyfish is this?

Friends of mine recently came back from a visit in kenya and on the kenyan beach they said they found several jellyfish with "sails" on their head. We tried finding out what they were and found one ...
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1answer
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What happens to deep sea creatures if they reach the surface?

Since deep sea creatures are adapted to incredibly high pressures, I would assume they would not be able to survive in the low pressure environment of the surface. What exactly happens ...
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1answer
83 views

Which fish species is it?

Today we found this kind of fish on the shore of Baltic Sea near Gdansk (PL). It is a very thin "fish" with some kind of a needle in place of nose. It was about 5 cm long and very lively. What is the ...
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202 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
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1answer
148 views

Do Cooper Hawks eat fish?

I have seen a Cooper hawk sitting on a low branch above my small Koi pond 3 times in 4 months. The books and net say they eat birds and some mammals but I wonder if he is looking at my fish ? Or ...
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2answers
180 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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1answer
40 views

What are the differences between Trachinotus and Bramidae species?

What are the differences between Trachinotus(Pompanos) and Bramidae(Pomfrets) ? ...like the difference between where they live/can be found, bone structure, etc.
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1answer
167 views

How do fish maintain razor sharp teeth?

I was watching a program about Barracuda - they have a front tooth that is supposed to be razor sharp. My kitchen knife goes blunt if I use it for long periods without sharpening. Sharks keep on ...
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1answer
2k views

Rock cod vs grouper

What is the difference between a rock cod and a grouper? The only difference I notice is that grouper seems to be bigger in size. But other than that, they are very similar.
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1answer
704 views

What kind of fish is this (Florida, USA)?

What kind of fish is this? It was caught in Florida (USA) in a canal and was in a group. It was about 5 or 6 inches in size.
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2answers
434 views

How do fishes “breathe” while eating?

First of all, a fish opens its mouth and water enters which passes through its gills. This helps in oxygenating its blood. So, if any food particle is in its mouth, how can it "breathe" i.e. how does ...
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1answer
3k views

What percentage of fish are herbivorous vs. carnivorous?

It appears that the majority of fish we eat are carnivorous, such as salmon and tuna. This got me wondering how common herbivores and carnivores are among fish species. I couldn't find an answer to ...
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1answer
217 views

Help identify these (two) fishes - Netherlands

Yesterday my kids caught these two fish. I tried to figure out what kind of fish (species and name, to tell my kids a bit more about them) they are but I was not successful. Today we made a trip to a ...
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2answers
393 views

Are lanternfish real?

Is there a real lantern fish existing in the world? If yes, kindly share a picture if one exists. I searched online for images, but most of them seem to be fake. The pictures I have seen on the ...
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1answer
108 views

Part of a fish outside the intestinal sac on the back?

I saw an expert Japanese chef fillet a mackerel (Scomber scombrus). He cut off the head and the whole intestinal sac came out with it as a single unit. Then he took the knife and scraped something ...
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1answer
466 views

Why do herring have fine bones

Most fish have largish bones which support the core muscles. Around the abdomen, they act as a sort of framework protecting the organs. With herring, the bones are really fine: almost thread like ...
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2answers
452 views

ID Fish from Florida?

This fish was caught in St. Augustine, Florida. What species is it?
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1answer
184 views

Trying To Identify this Fish

My 4 year old fell in love with this fish at the aquarium. I'm trying to find out what species it is so we can learn more about it.
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1answer
4k views

For fish, does a bony skeleton have any advantages over a cartilage skeleton?

I have learned that two important lineages of fish are the bony fishes (Osteichthyes) and the cartilaginous fishes (Chondrichthyes). Many websites mention an advantage of the cartilaginous skeletons ...
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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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2answers
158 views

Why is living on land beneficial?

When fish started developing the stronger limbs needed to walk(Slither?) onto land how was this beneficial? I cannot think of any form of food that would be helpful that would not be plentiful in ...
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1answer
511 views

What kind of fish is this? Spotted or largemouth?

I don't know if this is a weird looking largemouth bass or a spotted bass. It was caught in southern Oklahoma. Please help! Thanks.
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1answer
786 views

Worm found inside of wahoo

A fisherman from Hawaii wrote the following: This Fat juicy worm lives inside of every Wahoo that I catch. Inside the stomach. Right at the junction to the intestines. Sometimes there are two. ...
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1answer
311 views

What kind of fish is this? I don't remember the full name but it started with Tiger

name starts with tiger, forgot the rest, please help
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86 views

Why do most fish move fins orthogonally with their axis of symmetry?

So recently I read the question why are most fishes vertical (in the sense of distribution of their body mass) and it got me thinking what is the reason behind the direction they move their fins. My ...
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1answer
174 views

Evolution of Upside Down Catfish (Synodontis nigriventris)

My Biology teacher asked us to write 3 texts, explaining the evolution of the Upside Down Catfish Synodontis nigriventris, each one according to Lamarckism, Darwinism and Neodawrinism theories. She ...
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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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2answers
890 views

Why are most fishes vertical?

Why do most fishes have a "vertical" body shape instead of a "flat" one ? Here "vertical" means that the body(from a front view) is roughly orthogonal to the horizontal plane, and a "flat" body shape ...
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1answer
1k views

What kind of fish is this, caught in Cape Coral, Florida?

What kind of fish is this? It was caught in the canal in Cape Coral, Florida. The canals are clean brackish water — a mix of saltwater from the Gulf of Mexico and freshwater from the Caloosahatchee ...
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1answer
123 views

What kind of fish did I see in waters off a tropical island in the Philippines?

Found this while diving in the southern Philippines.
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2answers
182 views

Why are fish constantly in motion?

When I see fish in an aquarium, they never seem to stop swimming. This is in contrast to e.g. the penguins, who spend a lot more time just standing there. Is this true in the wild or specific to ...
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1answer
37 views

Why do Indian Major Carps spawn in running water?

I think running water serves as a cue necessary for hypothalamus to release GnRH into hypophyseal portal system which initiates a cascade of hormone actions ultimately leading to release of gametes. ...
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2answers
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Reason behind selection of sites of administration of pituitary extracts?

There are two ways by which pituitary extracts are administered in a fish's body during induced breeding of fish. Intramuscular injection is the most common practice in India and it is less risky in ...
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13k 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 ...
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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 ...
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1answer
78 views

Was mammal body better suited for some type of the marine environment than the body of fish?

When some of the land mammals came back to the oceans, they seem to be successful in the competition with fish at least in some environment even though they seem to have a huge disadvantage in the ...
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1answer
140 views

Can't identify this fish caught off NC coast

It was caught approximately 35 miles off the coast of North Carolina. I've been a charter fisherman for more than 25 years and never seen anything like it. Thanks for your help!
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1answer
101 views

Fish ID? Small, yellow-finned, tropical fish in Thailand

I have not had any luck finding the yellow fish shown in the photo in any of my fish books. I saw them in many places, so they are fairly common. This observation was at around 15 meter depth. I hope ...
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1answer
19k 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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1answer
78 views

Do they have scales? [closed]

Do Channa striatus and Channa punctatus have scales? They are both snake headed species of the genus Channa. I'm trying to figure out the distinguishing characters.
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1answer
134 views

Is there any evolutionary reason for why some organisms (wrasse) change their sex in adult stage?

In San Francisco, I saw this fish: and quoting the aquarium's page: Part of the wrasse family, the California sheephead is a protogynous hermaphrodite. Simply put, all sheepheads are born as ...
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1answer
2k views

What kind of fish is this?

What sort of fish is the big one in this picture? I saw it in an aquarium so I don't really know anything about its habitat.
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1answer
44 views

Are fish averse to extreme heat?

Terrestrial animals face two common sources of heat extreme enough to pose a danger to them: Sunlight and fire. It therefore stands to reason that they would evolve systems for sensing heat and ...
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Do clients of cleaner fish queue up?

I can't remember if I saw it in a cartoon, a documentary, or both, but the notion is that the clients of cleaner fish wait in line to be cleaned. "Clients" means the fish (or other aquatic animals) ...
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Fish and microplastic particles

How does exposure of fish to microplastic particles decrease egg-hatching and give young fish a craving for them? From Garbage in, garbage out: marine plastic 2016-06-24 | Espresso There is more ...
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261 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 ...
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1answer
114 views

Why is flash light harmful to what aquatic life forms?

When visiting an aquarium, it's often not allowed to take photographs with a flashlight on. It is said that the flash light with very high intensity is harmful to the displayed life forms. I respect ...