Keeping Goldfish

[Benc]

As I understand it, from a commercial point of view, goldfish colour depends on the temperature of the water during egg "incubation", many places I have netted showed up brown goldfish, totally distinct from the true crucian. Also, carp are certainly carnivorous, when I have netted lakes with large (20lb+) carp, small silverfish less than 6" have been bitten in half by these fish, they definately eat fish that are past the fry stage. Also, all the carp family produce alcohol as a by-product of respiration out of water, quite a bit too although I'm still waititng for goldfish beer!
Regards,

Ben

[wet]

A slight diversion (free diving = free spirit), how is this for evolutionary convergence?

Introversion of external hair (armor) to internal "teeth"

Balleen whales (blue, humpback, right whales) developed their balleen (whalebone stringy teeth) on the upper jaw, because their fish & mollusc eating ancestors had had walrus-like mustache whiskers which gradually migrated from the upper lip into the upper gums (over a period of a million years), changing from nerve-rich sensory bristles to long net-like filters, straining krill and small fish while allowing water to escape the mouth. (This is one of my hypotheses, haven't seeen any confirmation from others.)

Extroversion of internal teeth to external scales (armor):

Lamphrey (and hagfish?) types lack jaws, but have replaceable teeth which are used to grasp. Is it possible that fish scales derived from multiple teeth replacing (like in sharks, but non-jawed) in a previously non-scaled lamphrey-like ancestor? Various fish scales do resemble teeth in some way, although many have become ultra-smooth for high-speed hydrodynamics. Do fish embryos develop their scales in a cephalo-caudal direction starting at the head? Do primitive scaled fish have more dental-like scales?
Is this a new idea, or has anyone heard of it before? (This is another hypothesis)

Anyway, just seems cool that the opposite actions may have happened in fish and whales.

[Now consider that birds have feathers, which have bloodflow in the plume, do feathers derive from vestigial teeth in early aves which were developing beaks and bills and reducing their ancestral dentition? Are feathers malformed teeth with roots? Where did the beak come from? I don't know.]


DDeden

[naiad]

Originally Posted by Benc

As I understand it, from a commercial point of view, goldfish colour depends on the temperature of the water during egg "incubation", many places I have netted showed up brown goldfish, totally distinct from the true crucian.

The age at which goldfish become orange does vary with the temperature. That is why most small goldfish in the UK are imported from Florida, and fancy ones from the Far East. Those which are bred in the UK may take months or years to colour up. The brown goldfish which are released into fishing lakes are the unwanted brown ones from ornamental fish farms. They will probably never become orange.

Originally Posted by Benc

Also, carp are certainly carnivorous, when I have netted lakes with large (20lb+) carp, small silverfish less than 6" have been bitten in half by these fish, they definately eat fish that are past the fry stage.

I am surprised that they can bite a fish in half. Despite having no front teeth, they have leathery lips and gums and can grip quite hard with them, so that is how they must do the damage. My goldfish can pull leaves off plants by gripping them and shaking them from side to side.

Originally Posted by Benc

Also, all the carp family produce alcohol as a by-product of respiration out of water, quite a bit too although I'm still waititng for goldfish beer!

The carp, goldfish, crucian and tench can all survive for some time out of water, so it makes sense that they do. They produce energy by fermentation when there is no O2. Before fish could be transported in plastic bags, carp, tench and goldfish were transported in wet newspaper. They were said to survive longer this way than in a can of water, where they could be knocked about and bruised.

[naiad]

Originally Posted by wet

Balleen whales (blue, humpback, right whales) developed their balleen (whalebone stringy teeth) on the upper jaw, because their fish & mollusc eating ancestors had had walrus-like mustache whiskers which gradually migrated from the upper lip into the upper gums (over a period of a million years), changing from nerve-rich sensory bristles to long net-like filters, straining krill and small fish while allowing water to escape the mouth. (This is one of my hypotheses, haven't seeen any confirmation from others.)

The baleen plates of whales are modified hairs, made from keratin. They are not teeth. You are probably right that they started off as sensory bristles, and eventually became food filters.

Originally Posted by wet

Lamphrey (and hagfish?) types lack jaws, but have replaceable teeth which are used to grasp. Is it possible that fish scales derived from multiple teeth replacing (like in sharks, but non-jawed) in a previously non-scaled lamphrey-like ancestor? Various fish scales do resemble teeth in some way, although many have become ultra-smooth for high-speed hydrodynamics. Do fish embryos develop their scales in a cephalo-caudal direction starting at the head? Do primitive scaled fish have more dental-like scales?
Is this a new idea, or has anyone heard of it before? (This is another hypothesis)

The teeth and scales of sharks have an identical structure (denticles). Both are replaced constantly, as they do not grow as the fish grows and cannot repair themselves if damaged. Lampreys and hagfish have only teeth and no scales, so the teeth must have migrated from the mouth to the rest of the body when they evolved into sharks and rays.

Bony fish scales are very different. They are not like teeth, and are not replaced unless they are lost in an accident. They grow as the fish grows, and normally last for its lifetime. The teeth still have to be replaced, as they are similar to those of sharks and rays. The bony fishes must have lost the tooth-like scales on the body at some point, and re-evolved scales of a very different type.

They started off as plates in the skin, which fitted together edge to edge and did not overlap, like floor tiles. Gars, sturgeon and other primitive fish have these scales (ganoid).

Almost all the advanced bony fish species have scales which overlap, like roof tiles (cycloid and ctenoid). A few have naked skin, or plates made of bone.

Originally Posted by wet

Now consider that birds have feathers, which have bloodflow in the plume, do feathers derive from vestigial teeth in early aves which were developing beaks and bills and reducing their ancestral dentition? Are feathers malformed teeth with roots? Where did the beak come from? I don't know.

When the first fishes left the water, they lost their scales, which were probably heavy and easily damaged on land. Some primitive fish species (Australian Lungfish, Arowana) have these large heavy scales, so it is easy to understand why they lost them. This left them with soft moist skin, like modern amphibians. This is light and flexible, but has the disadvantage of losing water by evaporation and being delicate. At some point they improved on this by re-evolving scales, becoming the reptiles. These scales are different once again, being made of keratin (not living tissue, except at the root). Feathers are thought to have evolved from reptile scales. The beak is also made of keratin, like feathers. Hair is also thought to have evolved from reptile scales.

[wet]

Originally Posted by naiad

The baleen plates of whales are modified hairs, made from keratin. They are not teeth. You are probably right that they started off as sensory bristles, and eventually became food filters.

The teeth and scales of sharks have an identical structure (denticles). Both are replaced constantly, as they do not grow as the fish grows and cannot repair themselves if damaged. Lampreys and hagfish have only teeth and no scales, so the teeth must have migrated from the mouth to the rest of the body when they evolved into sharks and rays.

Bony fish scales are very different. They are not like teeth, and are not replaced unless they are lost in an accident. They grow as the fish grows, and normally last for its lifetime. The teeth still have to be replaced, as they are similar to those of sharks and rays. The bony fishes must have lost the tooth-like scales on the body at some point, and re-evolved scales of a very different type.

Seems that bony fishes ancestors had mutations which selected for calcium/phosphorus accumulation in the internal cartilage (bones) rather than calcium/phosphorus in the external scales, leaving the scales more flexible but the bones firmer. (I had thought this was due to living in freshwater, but now I think it was more likely a chance mutation.)

They started off as plates in the skin, which fitted together edge to edge and did not overlap, like floor tiles. Gars, sturgeon and other primitive fish have these scales (ganoid).

These sound like the difference between thin incisor teeth and wide molars, the base of the scales widened becoming plate-like. Perhaps a freshwater adaptation.

Almost all the advanced bony fish species have scales which overlap, like roof tiles (cycloid and ctenoid).

I think hydrodynamics is strongly influential with these types.

A few have naked skin, or plates made of bone.

When the first fishes left the water, they lost their scales, which were probably heavy and easily damaged on land. Some primitive fish species (Australian Lungfish, Arowana) have these large heavy scales, so it is easy to understand why they lost them. This left them with soft moist skin, like modern amphibians. This is light and flexible, but has the disadvantage of losing water by evaporation and being delicate. At some point they improved on this by re-evolving scales, becoming the reptiles. These scales are different once again, being made of keratin (not living tissue, except at the root). Feathers are thought to have evolved from reptile scales. The beak is also made of keratin, like feathers. Hair is also thought to have evolved from reptile scales.

I'm wondering where the reptiles got their keratin...I think there is a frog which during the larval stage has a keratinous snout and/or keratinous pseudo-teeth, this too could have spread from the mouth out around the body as scales.

Tadpoles with keratinous beaks, at tadpole photos:
Tetrapod Zoology : Frogs and toads: sheer, untold awesomeness

Ancient amphibian imprints: 3 naked salamanders
Experts discover rare amphibian imprints - Yahoo! News

Feathers, hair, beaks, horn, claws and fingernails are keratin protein.
Both meat and keratin are protein, but keratin has no nutritional value AFAIK.

Platypus males have poison ankle spurs, are there any fish with poison spines or glands on the rear non-caudal fins? (I forgot the proper name for the rear lateral fins) Catfish have poison spines on the front fins and dorsal fin but not on the rear fins AFAIK.

[naiad]

Originally Posted by wet

Seems that bony fishes ancestors had mutations which selected for calcium/phosphorus accumulation in the internal cartilage (bones) rather than calcium/phosphorus in the external scales, leaving the scales more flexible but the bones firmer. (I had thought this was due to living in freshwater, but now I think it was more likely a chance mutation.)

Possibly. The change from cartilage to bone was a gradual process, so many mutations must have been involved. The lampreys, hagfish, sharks and rays have an entirely cartilaginous skeleton. The sturgeons, lungfishes and other primitive fishes have some bone in the skull, but the rest of the skeleton is cartilage. The most advanced groups of bony fishes have an entirely bony skeleton.

The pearlscale goldfish is an example of a mutation in the calcium/phosphorus accumulation process in the bones/scales. It has calcium deposits in the middle of each scale (the 'pearls'). The skeleton seems to have lost out in the process - it is the shortest of all the fancy breeds, and is the closest a fish can get to being spherical. Swimming and buoyancy control are major challenges for this breed. Some are even shorter than the ones in the pictures.
http://www.bristol-aquarists.org.uk/...l/pearlscl.htm

Originally Posted by wet

I'm wondering where the reptiles got their keratin...I think there is a frog which during the larval stage has a keratinous snout and/or keratinous pseudo-teeth, this too could have spread from the mouth out around the body as scales.

Some frogs do have claws (African and South American clawed frogs) so they can produce keratin.

Originally Posted by wet

Platypus males have poison ankle spurs, are there any fish with poison spines or glands on the rear non-caudal fins? (I forgot the proper name for the rear lateral fins) Catfish have poison spines on the front fins and dorsal fin but not on the rear fins AFAIK.

The rear lateral fins are the pelvic fins. I can't think of any fish with poison spines on them, except possibly the lionfish, which has poison spines on most of its fins. This could be because the other fins are more easily used for defence. The dorsal fin can be used by a bottom-dwelling fish to fend off attack from above, and the pectoral fins can be stuck out as the fish lashes from side to side.

[wet]

[I sort of randomly copied from science blog Tetrapod zoology 3+ page article on frogs.]

Ghost frogs (so named because one species comes from Skeleton Gorge in South Africa) are a small group (6 species) of southern African species, specialised for clinging to rock surfaces along mountain streams [adjacent image shows Table Mountain ghost frog Heleophryne rosei]. Their tadpoles have an oral sucker-like disc and lack keratinous beaks (though they do possess denticles). Suggested at times to be close relatives of the Australasian myobatrachids (more on this group later), ghost frogs were found by Haas (2003) to be outside of Neobatrachia, and by Frost et al. (2006) to the sister-taxon to the rest of Neobatrachia (a taxon they named Phthanobatrachia). Genetic data led Van der Meijden et al. (2007) to link ghost frogs with the cannibal frogs* (Lechriodus), conventionally classified within Myobatrachidae, and the Chilean helmeted water toad (Caudiverbera caudiverbera) [a species I covered briefly here], conventionally - and probably erroneously - included within Leptodactylidae.

* It's a dumb name, given that cannibalism is not exactly rare among anurans.

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While Seychelles frogs have (virtually) always been regarded as neobatrachians, workers have disagreed as to whether they are closer to hyloids or ranoids, and this is still an area of contention. The four extant species of Seychelles frogs (the newest was named in 2002) are all tiny (SVL 10-40 mm) terrestrial frogs of leaf litter or arboreal habitats in high altitude forest [adjacent image shows tiny Gardiner's Seychelles frog Sechellophryne gardineri*]. They all lay their eggs on land; the young either undergo direct development, or the non-feeding tadpoles are carried on the back of the mother. They lack external vocal sacs and middle ear ossicles, so should be both voiceless and deaf... but they aren't, as at least some species make calls (Gerlach & Willi 2002).
[by Darren Naish at Tet Zoo]
Tetrapod Zoology : Ghost frogs, hyloids, arcifery.. what more could you want?

Incredibly diverse frogs and toads! Yet all based on quite similar body morphology.