I saw this fish...

[naiad]

I think sharks do have a lateral line. This is how they sense the low-frequency vibrations made by a struggling fish.

I don't know if any fish can hear out of water. The amphibians have ears with a middle and inner ear, and an ear drum on either side of the head. This is supposed to have evolved from the gill cavity. A tadpole has a gill chamber on either side of its head, like a fish. This leads to openings in the pharynx, so water can be taken in through the mouth and expelled through the gills. When it stops using its gills, it is left with the gill chamber, which becomes the middle ear. The outer gill opening is covered with a thin layer of skin (the ear drum) and the inner opening to the pharynx remains as the Eustachian tube.

Interesting to know that walruses allow water into their nasal cavity, maybe they can hear better underwater. Most seals make loud and simple sounds when out of water, suggesting that their hearing is not so good. They often make more complex sounds when communicating underwater.

I don't think any fish use echolocation. Some fishes use electro-sensing to locate prey by detecting the electrical impulses produced by its heart and muscles. These include the sharks and rays. Others produce electricity with special organs, and use it as a form of sonar to navigate. These include the elephant-nose fish, knife fish and electric eel. I don't think any sharks do this. The elephant-nose and knife fish also communicate with electrical pulses, which vary between species. Only three species use electricity to stun their prey or ward off predators. These are the electric ray, electric catfish and electric eel.

 

[wet]

Walrus spouting through nostrils, this is my basis for what I said.
http://ph.groups.yahoo.com/group/AAT/photos/view/2cf1?b=7

You didn't mention the air sac in fish/tadpoles regarding hearing, is there no direct physical link between the air sac and the ears? I didn't check any source.

I think sharks do have a lateral line. This is how they sense the low-frequency vibrations made by a struggling fish.

I don't know if any fish can hear out of water. The amphibians have ears with a middle and inner ear, and an ear drum on either side of the head. This is supposed to have evolved from the gill cavity. A tadpole has a gill chamber on either side of its head, like a fish. This leads to openings in the pharynx, so water can be taken in through the mouth and expelled through the gills. When it stops using its gills, it is left with the gill chamber, which becomes the middle ear. The outer gill opening is covered with a thin layer of skin (the ear drum) and the inner opening to the pharynx remains as the Eustachian tube.

Interesting to know that walruses allow water into their nasal cavity, maybe they can hear better underwater. Most seals make loud and simple sounds when out of water, suggesting that their hearing is not so good. They often make more complex sounds when communicating underwater.

I don't think any fish use echolocation. Some fishes use electro-sensing to locate prey by detecting the electrical impulses produced by its heart and muscles. These include the sharks and rays. Others produce electricity with special organs, and use it as a form of sonar to navigate. These include the elephant-nose fish, knife fish and electric eel. I don't think any sharks do this. The elephant-nose and knife fish also communicate with electrical pulses, which vary between species. Only three species use electricity to stun their prey or ward off predators.

These are the electric ray, electric catfish and electric eel.

Are all 3 fresh/brackish water fish?

 

[naiad]

You didn't mention the air sac in fish/tadpoles regarding hearing, is there no direct physical link between the air sac and the ears? I didn't check any source.

The air sac (swim bladder) is only connected to the ears in a few groups of fish, including the cyprinids (carp, goldfish, barbs, danios etc.), catfish, characins (tetras) and I think the loaches.

Are all 3 fresh/brackish water fish?

The electric ray is marine only. The electric catfish and eel are freshwater only.

 

[wet]

The air sac (swim bladder) is only connected to the ears in a few groups of fish, including the cyprinids (carp, goldfish, barbs, danios etc.), catfish, characins (tetras) and I think the loaches.

The electric ray is marine only. The electric catfish and eel are freshwater only.

I didn't expect that a marine ray would develop a strong electric shock. I wonder if it developed this talent in freshwaters long ago. Amazon freshwater rays are derived from Pacific ancestral rays, although now the Amazon ends in the Atlantic, I don't know if they use electricity for detection.

A tadpole has a gill chamber on either side of its head, like a fish. This leads to openings in the pharynx, so water can be taken in through the mouth and expelled through the gills. When it stops using its gills, it is left with the gill chamber, which becomes the middle ear. The outer gill opening is covered with a thin layer of skin (the ear drum) and the inner opening to the pharynx remains as the Eustachian tube.

So the tadpole's gill chamber becomes a middle ear, connected via the E tube to the pharynx, while the air sac becomes the lung connected via the larynx to the nostrils? I'll review the amphibians link.

Salamanders lack middle ears but have functional inner ears. I wonder if the inner ears are at the front of the lateral line, which has been enfolded somehow during the larval-adult transition.

Regarding breathing , lungs:
Newts and other pond dwelling species also tend to possess alveoli. The lungs of newts, and obligate neotenes appear to function more as hydrostatic organs. Cartilaginous rings are present in the trachea, and in some species, the bronchi. In most caudates, the trachea is relatively short, however, many aquatic species, such as Amphiuma spp., possess greatly elongated trachea resulting from the position of the lungs. Pulmonary respiration is usually supplemented by rapid throat pulsations (buccal pumping) that push air over the vascular lining of the buccopharyngeal (mouth and throat) region, and into the lungs, while others use their nares for ventilation. This is sometimes called "forced-air" breathing, and can be compared to diaphragm contractions as a means of ventilation in mammals".

Do you think "diaphragm contractions" refers to normal mammal eupneic breathing, or the apneic contractions of breath holders?

 

[naiad]

So the tadpole's gill chamber becomes a middle ear, connected via the E tube to the pharynx, while the air sac becomes the lung connected via the larynx to the nostrils? I'll review the amphibians link.

I think so.

Salamanders lack middle ears but have functional inner ears. I wonder if the inner ears are at the front of the lateral line, which has been enfolded somehow during the larval-adult transition.

Maybe. The lateral line has the same sensory cells as the inner ear.

Regarding breathing , lungs:
Newts and other pond dwelling species also tend to possess alveoli. The lungs of newts, and obligate neotenes appear to function more as hydrostatic organs. Cartilaginous rings are present in the trachea, and in some species, the bronchi. In most caudates, the trachea is relatively short, however, many aquatic species, such as Amphiuma spp., possess greatly elongated trachea resulting from the position of the lungs. Pulmonary respiration is usually supplemented by rapid throat pulsations (buccal pumping) that push air over the vascular lining of the buccopharyngeal (mouth and throat) region, and into the lungs, while others use their nares for ventilation. This is sometimes called "forced-air" breathing, and can be compared to diaphragm contractions as a means of ventilation in mammals".

Do you think "diaphragm contractions" refers to normal mammal eupneic breathing, or the apneic contractions of breath holders?

Interesting that the lungs of obligate neotenes function as hydrostatic organs. They are very negatively buoyant despite this.

Probably "diaphragm contractions" refers to normal mammal breathing.

 

[wet]

Sharks have short ribs too. Their toothy scales reduce drag, hmm, new wet suit idea... Huge liver and some are large brained as well.

(Link isn't really shark dissection, just shark trivia. I didn't know they could get a sun tan!)
Shark Dissection

 

[wet]

Piscidontist: "Open Wide"

rofl

 

[naiad]

rofl Where did you find that picture? It looks like a wels catfish, if it is alive I wouldn't risk that!

 

[wet]

I lost the source of the pic, but I remember it didn't say the name of the fish.

Here's another pretty boy, can you identify it? rofl
(I copied from Sandra Porter's <Digital Biology> blog at Science blogs.)

 

[naiad]

I tried to identify it, but I didn't find any flatfish with the eyes so close together. Maybe it is a juvenile dab or sole?

It's funny how the eyes have both moved to the same side, but the mouth is still in the normal place. rofl

 

[naiad]

Some more strange fish...
The fish in the first picture are at the same distance as the coin. They are about 1.5cm long, and probably adult. I think they are Microrasbora sp. Many of these have only been discovered recently. They are of the same family as the carp - despite being much smaller than a neon tetra or guppy!

The coral in the middle of the second picture looks like a hand.

 

[wet]

Bony vertebrate evolution: Elephant sharks closer to humans than teleost fish

Elephant shark shares closer genetics with humans than bony fish.
I guess because the shark has changed less since the last common ancestor than either humans or bony fishes.

Sharks have short ribs too. Their toothy scales reduce drag, hmm, new wet suit idea... Huge liver and some are large brained as well.

(Link isn't really shark dissection, just shark trivia. I didn't know they could get a sun tan!)
Shark Dissection

 

[wet]

Some more strange fish...
The fish in the first picture are at the same distance as the coin. They are about 1.5cm long, and probably adult. I think they are Microrasbora sp. Many of these have only been discovered recently. They are of the same family as the carp - despite being much smaller than a neon tetra or guppy!

The coral in the middle of the second picture looks like a hand.

Teeny fish, hard to catch on a hook and line, without a magnifying lens.
Do any of our resident spearos use a target scope on their speargun? That might help with getting such a difficult prey, but imagine trying to make a meal out of one!

The coral almost looks like a starfish, do you think it's a case of mimicry? What eats coral buds that doesn't eat starfish?

 

[naiad]

I can just imagine the argument about whether it is unsporting to spear them! rofl
Unfortunately they are now endangered, because they are being collected, not for food or sport, but for the aquarium fish trade. It is unbelievable that they have only just been discovered, and they are threatened by collecting.
Galaxy rasbora placed in new genus | Practical Fishkeeping magazine
Galaxy rasbora under threat | Practical Fishkeeping magazine

Some species of fish do eat corals, so maybe the coral is trying to look like a starfish. I don't think starfish have many predators. Some shrimps and crabs do eat them, keeping one as a 'living larder' and feeding on its tube feet. The starfish may survive this, as they have incredible powers of regeneration. Maybe the X starfish in my earlier post had grown the wrong number of arms. I have since seen another smaller X starfish, so maybe it is a father or mother now!

 

[wet]

I'm really surprised about the aquarium trade, I always thought it was done using "factory fish farms" rather than natural reef fish, which I thought would die in an enclosed aquarium. Like a zoo could more easily handle orphaned "tame" bear cubs than adult wild bears.
Pa-Ma Starfish: congratulations on your new clone!

 

[naiad]

Most freshwater aquarium species are now farmed. Some are imported from the wild because they are difficult or impossible to breed in captivity, or because it is simply cheaper to import them than to keep them. The Zebra Pleco is a good example - it was freely imported until recently, when imports were banned because it is threatened by overcollecting. It is now being bred in captivity, but as it is difficult to breed, they sell for about £400 each. Probably a good thing - makes people look after them properly!

It is a controversial issue - I think that if they are going to be kept for educational or conservation purposes, or if it is an alternative to eating them, it is acceptable, but I don't agree with the kind of large-scale collecting that is happening with some species.

Most marine aquarium species are wild caught, except some clownfish and seahorses. I haven't heard of any species that is threatened by this. The main threatened species are freshwater, such as the rasboras and clown loaches.

 

[land shark]

Huge liver and some are large brained as well

boy you guys really know how to kick a guy

For what its worth, it is my understanding that here in the US the fish farmers participate in a plan with the fish and wild life dept to keep certain species that are endangered in case of a disaster hopefully this also spreads out the gene pool.

 

[naiad]

That sounds like a good idea. I think it is good that people with the resources and knowledge to keep endangered species can keep some in case there is a disaster in the wild.

 

[joe123321]

Hey, Im going to get a new freshwater fish tank, probably 55 gallons. I really like bala sharks, but people say it is not good for them to be in a small tank, because they are so active and can get quite large. so, not leaning that way. So does anyone have any suggestions for some good fish to have? thanks if anyone helps

 

[naiad]

The bala shark (not a shark, but another member of the carp family!) is a beautiful and peaceful fish, but it is large, active and sociable, so you are right to choose something else.

The selection of fish will depend on whether the water in your area is hard or soft.

For reasonably soft water:
Tetras (neon, glowlight, x-ray and many others)
Angelfish (but there are a lot of unhealthy mass-produced angelfish around at the moment)
Corydoras (bronze, peppered, panda and many others)
Bristlenoses (Ancistrus - one of the smaller plecos and funny looking, may even breed in the tank)
Otocinclus (very small pleco, about 3cm, can get lost in the tank!)
Small barbs (cherry, rosy, golden)
Kribensis cichlids

For hard water:
Platies (in my experience one of the easiest tropical fish, and some beautiful varieties such as the Moonlight and Sunset platies)
Swordtails
Guppies (can be surprisingly difficult!)
Mollies (can be difficult, may need salt in the water, which means they can only be kept with other salt-tolerant fish)
Malawi cichlids (only with other Malawi cichlids, not with any other species)

For an unheated tank (in a normal temperature house!):
Weather loaches (can escape, so need a tight fitting lid!)
Paradise fish
White Cloud minnows (very small)
Zebra Danios
Goldfish (many different colours and breeds, will eat very small fish, so only with other similar fish or with Weather loaches)

I will post any more I find. They may have different names, so if you don't know what they are, I can give you the Latin name.

Lucia