Selasa, 29 Mei 2012

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Minggu, 20 Mei 2012

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Make way for the half ton Sturgeon

Make way for the half ton Sturgeon

Make way for the half ton Sturgeon

Copyright © Eliezg, Creative Commons

Fishermen in north eastern China got a surprise catch when they turned up a Kaluga sturgeon, Huso dauricus, weighing in at 617kg.

Chen Li, the fisherman responsible for the catch claims the fish is the largest he's ever seen.

A protected, critically endangered species in China, this monstrous predator that hunts on Salmon has been known to capsize fishing boats, and even drown fishermen. (The picture above shows a much smaller preserved specimen at the Khabarovsk Regional Lore Museum).

The maximum size for these fish is considered to be somewhere around 1,000kg, but some estimates suggest that fish of up to 1,500kg may exist, making them the largest freshwater fish in the world. Compared to the meager 200kg or so of Arapaima this fish is something of a leviathan.

Although protected, these fish are still sometimes poached for their valuable caviar, and the fish caught here was brimming with eggs — around 1.2 million of them.

However, in a pleasant twist of fate, rather than ending up being killed and eaten, she was instead carried to a local Sturgeon breeding station, where staff will collect roe and artificially inseminate to create young.

Any fry produced are released into the Heliongjang river, where the giant was caught.

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Published: Nathan Hill Thursday 17 May 2012, 3:59 pm
Views: 2,546 times
Filed under: sturgeon predator largest fish giant freshwater kaluga China Huso dauricus



Sabtu, 12 Mei 2012

Heiko Bleher discovers: Apistogramma

Heiko Bleher discovers: Apistogramma

Copyright © Heiko Bleher

Heiko Bleher reveals some of the Apistogramma species which he found recently in South America.

Apistogramma sp. aff. personata (pictured above)
Origin:  Río Inirida caño near El Remanso, Colombia/Brazil.
Water: pH 5.41, conductivity 14-21 µs/cm, temperature 30.5°C/86.9°F (15.00 hours).
Habitat: Caño with sandy bottom covered with leaves, driftwood, fallen-in trees and shady with overhanging trees. The water was tea coloured, had hardly any aquatic vegetation and in a flooding rainforest region.
Notes: A. personata was described by Kullander in 1980 from the Rio Uaupés, near Assai in Brazil, near the Colombian border, and some 500km/310 miles east of the Inirida location where I found it.
Distinguished from A. personata by tail pattern which in the described species clearly comprises eight black dotted vertical lines, and the scale spots are less pronounced.
A. personata is mentioned at 4.42cm/1.74" TL and this specimen was 8.2cm/3.23". Affinities are otherwise very much the same.
Aquarium: This needs slow flowing water and the aquarium should have areas of low light, floating plants or a Philodendron growing into it, or better roots of other terrestrial plants. If wanting tank mates select only small characoids and/or dwarf cichlids. 

Apistogramma cf. iniridae
Origin: Caño Sardiña, Inirida basin, Colombia.
Water: pH 4.8, conductivity 19 µs/cm, temperature 28.5°C/83.3°F (09.30 hours).
Habitat: Slow flowing creek with sandy bottom covered by leaves, driftwood, fallen-in trees. Overhanging trees offered shade. Black water with no aquatic vegetation, but many tree roots, Philodendron and other terrestrial plant roots.
Notes: More than 70 species of Apistogramma have been described from South America, east of the Andes. There are possibly around twice as many more to be identified next to a number of populations. 
I found at least six different populations of A. iniridae, Kullander, 1979, and, sometimes within a single habitat, two or three different colour patterns. Type locality is the Inirida basin.  
Aquarium: Perfect for larger nanos with sandy bottoms, few plants, driftwood and leaves. The tank should have a slowly flowing filter, as these fish are used to still water. They breed easily, but males are territorial. 

Apistogramma bitaeniata
Origin: Small right-hand caño near the mouth of the Rio Taraira, which forms the border between Brazil and Colombia.
Water: pH 5.56, conductivity 29 µs/cm, temperature 26.5°C/79.7°F (16.30 hours)
Habitat: A tiny clear creek with water less than 5cm/2" deep. There was no aquatic vegetation, but many leaves, driftwood, palm leafs and fallen-in trees and roots. The water flowed very slowly.
Notes: This has the typical morphologic characters of the species described, but colour pattern is quite different. This species had never previously been found so far north from its type locality. 
Aquarium: Perfect for a smaller aquarium, with maybe some plants, such as Mayaca fluviatilis, light water flow and some floating plants (Azolla species). The bottom should be of sand and it would be beneficial to add soaked leaves.

Apistogramma bitaeniata?
Origin: Caño La Libertad, a tiny tributary of the middle Río Apaporis near the waterfall La Libertad in Colombia.  
Water: pH 6.56, conductivity 19 µs/cm, temperature 27.2°C/80.9°F (10.00 hours) at 125m/410' above sea level
Habitat: A clear water creek with water only 10cm/4" deep. No aquatic vegetation, but many leaves over whitish fine sand 
and gravel. Fallen-in trees were covered with mosses, as were large rocks. This was thick jungle and the water was slow flowing.
Notes: Possibly a variant/population of A. bitaeniata. It does have some A. bitaeniata morphologic characters, such as the tail pattern and forked shape, but colour pattern is different and so far it has not been seen in such a bright yellow, or golden head, breast and lower former body pattern. This location is far from any other A. bitaeniata known habitat. 
Aquarium: A beautiful Apistogramma and ideal for smaller aquariums with fine, perhaps white, sand, light flow of water and some floating plants. Well-watered driftwood should also be included and small pencifishes of the genus Nannostomus, and some Carnegiella species would makes suitable mates.

Published: Heiko Bleher Thursday 10 February 2011, 7:17 am
Views: 963 times
Filed under: cichlids Apistogramma Heiko Bleher

Kamis, 03 Mei 2012

Why aren't cichlids hard any more?

Why aren't cichlids hard any more?

Why aren't cichlids hard any more?

Copyright © Practical Fishkeeping

Today's cichlids are nothing but wimps and wussies, compared to how they were a decade or two ago, says Nathan Hill. So what happened to turn these tigers of the aquarium world into pussy cats?

Bullies, bruisers and bad boys. When I started in this trade there were fish that came up to the glass and tried to tear your face off if you looked at them funnily.

It seems that the last two decades of intensive farming have not only produced some runts, but also some wussies, and personally I'd love to know what happened to make them this way.

Here's a handful of the fish I think have gone totally sideways…

You probably wouldn't think the Firemouths are that tough a fish, but by jove they used to be. This is the species that would happily flare its throat at an aquarist as much as a rival male, and then back it up with a hefty nip when you tried to do some tank maintenance.

But nowadays, they're more Ghandi than Ghengis Khan, happy to stay out of trouble's way, grubbing about for food, and getting roughed up by a passing Kribensis.

In the wild these tough Central Americans are used to holding their own against other fish, and clearing the way when they spawn. But it seems that farming has reduced these once ferocious bulls to the aggression levels of a kitten. After all, when was the last time you saw a wild Firemouth? It'll be a while, I'll wager, with almost all the fish we see being raised in the Far East, or Eastern Europe.

All I can guess is that the mass-rearing conditions, combined with a reduced incentive to display traditional behaviours are having a cumulative effect. After all, it's well understood that many fish learn their behaviours from others.

It seems a sad, self-fulfilling prophecy that we eventually put the 'meek' into Thorichthys meeki.

What happened here? I used to be scared of Convicts, many years ago. They were the aquatic equivalent of Britain's most violent inmate, Charles Bronson. In fact, if the two had to share a cell, I know which my money would be on.

The Convict was for years the stereotype of toughness in a fish. A breeding pair would create an impenetrable fortress from their own bodies, and many a tank would be taken over by an amorous couple.

They'd punch above their weight, too. I'd have calls from aquarists that had stuck them in with bigger fish like Jack Dempseys, only for the Dempsey to end up cowering in a corner while the convicts pummeled scales off of it. They could truly stand up for themselves.

But like the Firemouth, it would appear that unless you get a wild one, you're doomed to have a sap. They don't even have the colours any more. I remember bodies the sheen of gunmetal, with jet-black stripes and necks of flame. Now it's a kind of tepid grey on grey with a hint of orangey pink. If you're lucky, that is…

I'm pretty sure I'll get heckled for this one, but what the hey. I'm saying it anyway. Oscars are wimps these days.

They were always considered a companion animal rather than a fish, but even so they used to have a temper on them. Many times I recall having to separate an Oscar and a plec in one of my sumps, the latter in the mouth of the former, unscathed and giving as good as it got.

But nowadays, aside from a little juvenile inquisitiveness, or maybe the occasional grab when a finger is mistaken for food, they're about as aggressive as a sheep.

Again, get me a wild specimen, and I'm sure it'd be a different story.

But then, is this even a bad thing? Do we want violent fish if we can have peaceful ones? I know that we prefer peaceful pets in general, and that's understandable. But I can't help to think we've lost something of the inherent wilderness present in these fish. And wasn't that the point in keeping fish? To bring a little nature into the home?

I'm keen to hear your thoughts on the subject.

Green terror/Blue acara
What on earth has happened to these two? I went to a retailer's a while ago and had to ask what the hell the fish were in the tank. I was told that the vaguely marked, pale, anaemic looking fish on show were Blue acara. I'd always had the impression that these fish were quite stocky, with vibrant markings. I guess I was looking at the wrong species for the previous 20 years.

If ever there was a call to arms for the quality, small breeder in the UK, it must be for these fish. I implore you, import some wild Acara, or Green terror – which have gone exactly the same way – and start a programme of reintroduction into the hobby. Because all the ones I'm currently seeing are pretty awful.

Feel free to send me pictures and prove me wrong, anyone…

Longfinned, golden, balloon, or just outright disappointing, the Ram is a species that I remember as quite a lairy little fish. When not keeping tetra at bay, mine used to square up to inquisitive Angelfish, relocate stocky Ancistrus, and even have the nerve to flare up at gouramis thrice their size.

But no more. These days the Ram is a shadow of its former self, happy to keep its nose clean until feeding time, and backing down from passing Apistogramma.

Plus, I'm not sure if it's just me that's seeing them, but there seem to be an awful lot more runts than I remember, especially around the mouths. To take a close look, head on, one might almost think that you were peering at a deformed Parrot cichlid, rather than these classic aquatic gems.

Over to you

Admittedly, I get out to a lot of shops these days, and see a lot of fish, but I'm sure there are still plenty I'm overlooking. Have you got any cichlids that you can think of that used to be solid, but now seem way too laid back? Let me know, I want to hear about the others I'm not seeing.

Or maybe you just disagree with me. Let me know what you think it is I'm witnessing instead. Because I'm pretty sure I'm not imagining this…

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Published: Nathan Hill Thursday 3 May 2012, 9:32 am
Views: 903 times