Speaking of TSN runts, dinks, and Co...

thebiggerthebetter

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The new TSN from Matthew added 4 inches in 2 months and likely started to bother the smallest tank mates - a glass catfish and chinese hifin, so trying it in a different tank:

 

jjohnwm

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Viktor, perhaps you (or anyone else...) could clarify something for me.

We frequently read that the TSN's and TSNxRTC's and probably others in the hobby are simply culls from commercial breeders who raise these fish for the food trade. Many of them, the hybrids especially, have those weird misshapen heads and mouths which label them as substandard fish right from the get-go.

But a lot of others simply look, at least to my untrained eye, like perfectly normal TSN cats, with nothing glaringly "wrong" with them...but they still seem to be very prone to the short lifespans that are the topic of this thread.

What is it about them that attracts attention to them in a facility with probably thousands of similar fish being raised up together? Are they simply catching the eye of the breeders because they have unusually slow growth and are outstripped by their siblings in the same tank? This seems reasonable, but then you and others describe instances where these fish grow like gangbusters in a hobbyist tank. How much faster could they possibly grow in a hatchery, to keep up with the others with them?

Again, I'm not talking about the obvious weird ones, but rather the ones that seem "normal" and yet are somehow identified and culled out, to show up in aquariums?
 

thebiggerthebetter

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I'd agree with everything you wrote as statements. Both of the fish you mention are also cultured in SE Asia cheaply and relatively poor quality but with the goal of selling them in the ornamental fish trade, I assume, not for food. My understanding the culling in the food fish operations is done by size, they are sifted, the small faction is removed. A lot of these happen to have deformities too. They go through millions of fish, impossible to pluck out many by searching out the obviously deformed ones.

My impression they grow faster at farms. The usual marketable size of 1.5 ft is reached in 6-8 months starting from an egg. We in the hobby almost never see any such fast growth rates.
 
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thebiggerthebetter

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thebiggerthebetter

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A dream has come true! Chase Widmer gifts us a true spotted TSN Pseudoplatystoma corruscans! (A link to his video will follow later.)

 

Fishman Dave

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Viktor, perhaps you (or anyone else...) could clarify something for me.

We frequently read that the TSN's and TSNxRTC's and probably others in the hobby are simply culls from commercial breeders who raise these fish for the food trade. Many of them, the hybrids especially, have those weird misshapen heads and mouths which label them as substandard fish right from the get-go.

But a lot of others simply look, at least to my untrained eye, like perfectly normal TSN cats, with nothing glaringly "wrong" with them...but they still seem to be very prone to the short lifespans that are the topic of this thread.

What is it about them that attracts attention to them in a facility with probably thousands of similar fish being raised up together? Are they simply catching the eye of the breeders because they have unusually slow growth and are outstripped by their siblings in the same tank? This seems reasonable, but then you and others describe instances where these fish grow like gangbusters in a hobbyist tank. How much faster could they possibly grow in a hatchery, to keep up with the others with them?

Again, I'm not talking about the obvious weird ones, but rather the ones that seem "normal" and yet are somehow identified and culled out, to show up in aquariums?
I have to admit that I am not a believer that many we get in the fish trade to be culls from fish farms or food fish. Certainly here in the UK anyway. As the fish we get tend to be around 2” in length and at that size I believe they would simply be too small or too delicate to go through the sorting process. (Although they could conceiveably be slower growing ones of a batch I guess but I have different experience below which suggests not). I do however believe it to come down to genetics of the chosen parents somewhat. If poor parents are chosen we get poor fish. I also think that too many keepers start them in too small tanks and feed them incorrect foods. When kept with guppies they gorge themselves constantly and grow at a rediculous rate (an accident quickly learnt!) but they also become unhealthy due to the lack of fasting. I believe that these fish produce so many offspring on the chance that the strong ones will survive to be good healthy fish. I think we are farming them and keeping them all, hence just also getting the ones nature would simply have removed herself. Hence, some good ones, many bad ones, no culling or prior selection as such involved. Not at 2” anyway.

Victor,
Yes, noticed the tail too but not sure if it’s just the look due to his slim appearance. Would be nice to see him once he has eaten and started to bulk up a little.
All the best with him!
 
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thebiggerthebetter

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You may be right, Dave. Although the picture in my head differs, it is but based only on suppositions. I am sure farmers have efficient and non-traumatic techniques to sift their fish from very small sizes, e.g. as simple as separating the smallest of the batch by installing a mesh and offering feed on the other side, so only the smallest under-growers swim through and the desirable bigger kin remains. This, too, is a supposition :)

Then of course let's not forget the same fish species but widely, crudely and cheaply raised in SEA not for food but specifically for aquarium trade. They seem to be on average of sub par health / prospects.

***

Back to our corruscans. I appreciate your comment Dave. Russ wednesday13 wednesday13 would you say it caught your eye or does the tail end past adipose look fine to you?
 
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