killifish keepers unite!

[TyroneGenade]

Hi all

Please go have a look here: http://en.wikipedia.org/wiki/Killifish

This link was passed on to me by a friend trying to convince me to contribute to the Open Souce movement. I do not want to tackle this alone and feel that we here on the forum can best tackle this entry together to yeild a short and concise explanation of what a killifish is.

Here is my opinion:

Killifish belong to the order Cyprinodontidae. This order is
composed of several families including that of Poeciliidae that
includes the guppy. The term "killifish" generally restricted to
the egg laying members of this large group of fish.

Killifish can be found in the Americas, as far South as Argentina
and as far North as New York. They can also be found in southern
Europe, most of Africa as far south as Kwa-Zulu Natal, South
Africa. Killifish also occur in the Middle East, and Asia (as far
east as Vietnam) and several Indian Ocean Islands. Killifish are
not found in Australasia.

The majority of killifish live in permanent streams, rivers and
lakes and live between 2 and 3 years. Such killifish are common in
the Americas (Cyprinodon, Fundulus and Rivulus) and
Africa/Asia (Aphanius, Aphyosemion, Aplocheilus, Epiplatys,
Fundulopanchax, Lacustricola etc...).

Some specialized forms live in temporary ponds and flood plains.
In Africa one finds the fish of the genus Nothobranchius
and in South America several genera ranging from the cold water
Austrolebias of Argentina and Uruguay to the more tropical
Gnatholebias, Simpsonichthys and Terranatos. These
may live only a few weeks in the wild but generally live 1 or 2
years in captivity.

There diet is primarily aquatic arthropods such as insect
(mosquito) larvae. It is reported by the killifish collector
Rudolf Koubek that areas in Gabon where the streams lack killifish
(due to pollution or other causes) are rife with Malaria.

Most species are easy to keep and breed in the aquarium. Specimens
can be obtained from specialist societies such as the American
Killifish Association, British Killifish Association or Deutsche
Killifisch Gemeinschaft etc... A good reference source of
killifish information is the http://www.killies.com/Forum.

Comments?

[whuntley]

My main comment is that you did not mention that many are among the most colorful of fresh water fishes, and often with the most interesting markings and shapes.

Behavior varies from open-water schooling (Lampeyes) to nest-building and guarding (Pupfish).

"..temporary ponds and flood plains." fails to explicitly point out that the eggs can go through a semi-dry period in mud and hatch during the next rainy period. [I always tended to like the term "Instant Fish" but others fail to share my enthusiasm for it.]

"There diet is primarily aquatic arthropods..." should be "Their diet is etc...."

Wright

[TyroneGenade]

Thanks Wright...

I didn't aim for perfection the 1st round. As soon as more commentary comes in I will redraught it with the suggestions.

Thanks

[whuntley]

Hey Tyrone,

It was a lot more complete and polished than most of my first drafts.

Go for it!

Wright

[timebomb]

Great article, Tyrone.

But there's something missing. I've often wondered about this - What makes a fish a Killifish? In other words, what do they all have in common?

If you compare say, a Notho to an Aphyosemion, they are so different in many ways. Their life spans, breeding cycles, body shapes are different yet they're belong to the same group. So what is it that makes them the same?

Loh K L

[hwchoy]

So what is it that makes them the same?

Loh K L

their phylogeny

[whuntley]

So what is it that makes them the same?

Loh K L

their phylogeny

Very funny!

They are carps as opposed to minnows or silversides, and they have teeth but don't give birth alive. Egg-laying toothed carps is the general group to which they belong. Live-bearing toothed carps, like guppies, are very closely related and differ mostly in the fertilization and gestation process.

That gets a little blurred when you find that Cynopoecilus melanotaeniea are actually internally fertilized but then lay fertilized eggs that hatch outside momma's body. There are probably others, for the "Fighting Gauchos" went for many years before folks discovered their strange breeding situation. Some Tetras and fishes of other kinds also show this trait.

One silversides group (honorary killifish), the Medakas, have eggs fertilized while still attached to the mother, but dangling outside her in a cluster. She then goes to find plants to attach them to for gestation.

Most bizarre of all is the Cory cats who are internally fertilized because she swallows it! Their short gut allows the sperm to pass through her in seconds with being destroyed by digestive processes. Then she places the sticky pre-fertilized eggs on plants or the glass.

Among killifish, a wild variety of ways have been developed to assure that the fertilization and gestation processes get a statistically meaningful way to procede.

Some spawn on plants and let the law of averages work.

Others bury eggs in the mud where they are hard to find and eat.

Some drive them into crevices where they get a lot of oxygen and current but are protected from being swept away or eaten.

A few even act like chicklets or sunfish, and build nests that they guard,

Some of the most resourceful quit being killies and learned to give birth alive. Sure defeats those egg-eating trumpet snails!

Hope that puts killies into their proper place in the scheme of things.

Wright

PS What's a phylogeny? Some kind of shark? :^)

[hwchoy]

mmm… that's explaining WHAT killifishes are, which timebomb already knows. he wants to know what MAKES THEM THE SAME, which I still think the right answer is phylogeny: the sequence of events involved in the evolutionary development of a species or taxonomic group of organisms.

or in simpler english, their ancestral history as a related evolutionary group of fishes.

[TyroneGenade]

Ok, how does this sound:

Killifish belong to the order Cyprinodontiformes. This order is composed of several families including that of Poeciliidae that includes the guppy. The taxanomic definitions of the order are addressed in Costa 1998 ("Phylogeny and Classification of the Cyprinodontiformes (Euteleostei: Atherinomorpha): A Reappraisal". Parte 6 (Atherinomorpha) de "Phylogeny and Classification of Neotropical fishes". Malabarba, LR; RE Reis; RP Vari; ZM Lucena & CAS Lucena (eds) Porto Alegre, Edipùcrs, 603 p.).

The term "killifish" is generally restricted to the egg laying members of this large group of fish. This term also includes the Ricefish or Medakas (genus Oryzias) of the order Beloniformes.

Killifish can be found in the Americas, as far South as Argentina and as far North as New York. They can also be found in southern Europe, most of Africa as far south as Kwa-Zulu Natal, South Africa. Killifish also occur in the Middle East, and Asia (as far east as Vietnam) and several Indian Ocean Islands. Killifish are not found in Australasia.

The majority of killifish live in permanent streams, rivers and lakes and live between 2 and 3 years. Such killifish are common in the Americas (Cyprinodon, Fundulus and Rivulus) and Africa/Asia (Aphanius, Aphyosemion, Aplocheilus, Epiplatys, Fundulopanchax, Lacustricola etc...).

Some specialized forms live in temporary ponds and flood plains. In Africa one finds the fish of the genus Nothobranchius and in South America several genera ranging from the cold water Austrolebias of Argentina and Uruguay to the more tropical Gnatholebias, Simpsonichthys and Terranatos. These may live only a few weeks in the wild but generally live 1 or 2 years in captivity.

Some species will shoal while others will exhibit anti-social tendencies where territories are fixed and fiercely defended. Many species exist as passive tribes in small streams where dominatemales will fix and defend a territory while allowing females and immature males to coinhabit the local area.

The diet is primarily aquatic arthropods such as insect (mosquito) larvae. It is reported by the killifish collector Rudolf Koubek that areas in Gabon where the streams lack killifish (due to pollution or other causes) are rife with Malaria. Some species of Megaupsilon from Lake Titicaca are planktonic filter feeders. Others, such as Cynolebias and Megalebias species and Nothobranchius ocellatus are predatory and feed mainly on other fish.

Reproductive strategies are diverse. Some will spawn in no specific location while others will spawn at specific sites or on specific environmental structures (e.g. Lamprichthys tanganicanus in rock crevices). Some species (e.g. Cyrinodon) will establish "nests" on the substrate wherein the male and various females will spawn. The annual killifish will spawn in the mud of the temporary ponds and floodplains. In the mud the eggs will cease development (diapause) dependent on the environmental conditions. There is some evidence that where the ponds do not dry out the eggs will develop as normal and hatch in the water. Where the ponds dry out the eggs will lie semi-dormant, developing slowly until the ponds fill again where upon the fry will hatch from the eggs and
establish a new generation. Species of the genus Cynopoecilus practice internal fertilization.

Many killifish are lavishly coloured; and most species are easy to keep and breed in the aquarium. Specimens can be obtained from specialist societies such as the American Killifish Association, British Killifish Association or Deutsche Killifisch Gemeinschaft etc... A good reference source of killifish information is the http://www.killies.com/Forum.

I will deal with scientific names (italics) later on. For now, any comments?

[erikthur]

I suggest that the heavy information in the first paragraphe comes closer to the bottomline. I fear that many people wan't get thru the first paragraphe as it is now written. Easy up at the start (once trained by media specialists for at least one hour in Chicago before a press conference)...
Thus, I like the start of the first draft better.