Amazing Posts & comments gents, thanks for contributing.
I can only dream of having setups of the likes that you two have managed, but Im getting there.
Some very interesting points Arapaimag/Viktor.
I think the same came be said of a large majority of not just cats but most fish species in that they will act differently in accordance to their environment.
Especially with regards to lowered aggresion in relation to tank space.
I've kept several species of fish over that years that in one setup will be super aggressive only in another to be fine.
The H.Filamentus I kept years ago would be a perfect example - took it of the shop for free because they just couldnt house it with anything, placed it in my 500G Pond with some bigger Cats (20"-28") & it was super placid!
I would imagine that Arapaimag's Jau met its demise at the jaws of one of the Leerii perhaps? Would be difficult I guess to keep a close eye on certain fish that hide in such a large setup and also I would assume most of the aggression or territorial disputes to be during the hours of darkness.
From my own experience - my cats kept in the heated ponds are much harder to keep a close eye on than my Cats in large full frontal glass aquaria and have to be carefully observed during feeding - hand feeding is not only great fun but essential for viewing/observation
As for my mini beauties, they're doing great.
Proving to be very nocturnal & Hide all day but will shoot out and back again to grab Earthworms placed in the aquaria.
Will see what i can do with regards to pictures as short of taking them out, pictures will be night time shots which aren't going to make great viewing Im afraid