What's the maximum size that SILURUS ARISTOTELIS can reach to?

But now I rely get in sorrows. They are under water for 5 hours now. Does anybody, who has these fishes in his (or her) tank, know, how long it could take, till they get back to the surface?

The fishes are here now. I´m shure that it are fossilis. In the internet and in books you can read, that it comes to the surface in every 15 minutes. But they are under water now for around 1 hour.
Is this normal? And how long can they stay under water without getting atmospheric oxigen?

@magnum4

Just to answer your last sentense: I did not purchase this fish, before doing research. I´ll buy the fishes tomorrow and I started research two weeks ago.

Now I don´t know whom I should trust. The one says It isn`deadly, the other says it is. What´s correct?

Achim wrote this: Seriously, there are at least two species of Heteropneustes which are sold as H. fossilis, a uniform grayish/black one and a rather brownish with a creamy lateral stripe.

The fishes that I`ll buy are the brownish ones.
Are they rarer then the other ones?

I`ll buy two juvenil Heteropneustes fossilis on Tuesday and I want to be informed about their poison, so I have some questions.
1.What are the sympthoms of it?
2.How can it be transisted?
3.Is it deadly?

Thanks for answering my questions

Simon

PS:Excuse my bad English :roll:
PPS:Greetings from ...