Plj

HI bros,is there any way in preventing an arowana from having PLJ or is it unavoidable as it is in it's genes and is there any way to spot a potential PLJ in young fishes?

From my point of views, plj is caused by genes so no cure...

Originally Posted by Hades

From my point of views, plj is caused by genes so no cure...

AGREE WIF U...

[Voltron2000]

Originally Posted by Huat22

HI bros,is there any way in preventing an arowana from having PLJ or is it unavoidable as it is in it's genes and is there any way to spot a potential PLJ in young fishes?

Personally i find, the PLJ issue very subjective. Some classify PLJ when the lower jaw overgrows/ exceeds the top jaw. Some classify PLJ when the lower jaw is in line with the top jaw. So which is which, is your choice...

If the aro is small and has very slight plj, you may try pumping up it's body mass.

I look out for plj by not looking from the side of the aro. I look from the front (when the fish facing you). When you can see the top jaw, then it's ok. If the top jaw is not visible (covered by the lower jaw), though from side view the lower jaw has not exceeded or in line with the top jaw, then the chances of it having plj is high. Viewing angle is important (hope you understand what i mean).

Personally for me, as long as the LJ does not outgrow the TJ, is ok for me.

Cheers

[Hobbit6003]

Hi Huat22,

A long while ago, I've posted an explanation on PLJ. Let me retrieve for you here.

Protruding mandible or lower jaw, is a phenomena due to a developmental anomaly, or should I say, a developmental deviation from the norm.

Ideally, we can classify this phenomena into 2 broad category:

1. True mandibular prognathism

This is the instance whereby the mandible is truly overgrown as compared to the upper jaw. In these cases, genetics dictates.

2. Relative mandibular prognathism

I would attribute this phenomena to the underdevelopment of the upper jaw, which thus results in the lower jaw being protruded, even though it is growing at a normal rate.

This again, is largely due to genetics, although in some instances, 'pumping' the aro with frogs for a period of time does help with the upper jaw catching up with the lower jaw, and thus correcting the reverse overbite, as one of my experienced aro friend attests to this.

I think, if the upper jaw is underdeveloped due to genetics, then I would say that it is impossible to correct. However, if the upper jaw is developing at a slower rate due to a nutritional problem, or for whatever physiological reason, the upper jaw would catch up sooner or later.

Again, as in many mythical aro issues like the drop eye, nobody has a concrete rationale to such a phenomena. I think in order to scientifically classify PLJ, an epidemiological study would have to be conducted to find out:

1. The average normal length of the upper and lower jaw of the various variety of asian aros

2. The prevalence of such a phenomena in each variety

3. The variance in the various reverse overbite (measured as the vertical distance between the tip of the lower jaw to the tip of the upper jaw)

4. The age of occurrence of the PLJ, the age of the aro when the optimal overbite is attained

5. The prevalence of correction of PLJ with age, and the avg age that PLJ disappears in these aros.

The epidemiological studies would then form a basis to find out:

1. The various contributing factors besides genetics, if any.

2. The various correcive technique that can be adopted.

3. The type of PLJ that can be corrected with the respective techniques, and the prognosis of such applications.

I'm sure the above list is by no means exhaustive, so I hope to see more researches to be conducted on the asian aros, so as to unlock more mystery and myth of this majestic creature.

Cheers,

Kenny

[dalelad]

cheers for the very fine explaination, Kenny!

Bro

Bravo!

Good Job Done bro, very detailed explaination,maybe can make it sticky so that newbies like me will know