would a group of 3-5 H. longimanus work? i had 6 spinifer in a group last year and they all killed eachother and the last one died of old age a few weeks after killing its tankmates...
so what do you think? they would be in a 2' x 1' x 1' with multiple hiding places..

I've had eight from the same brood together in a 10-gallon for a couple years now, and only lost two (started with 10).

is that because they were related?

Dunno. It's the only community I've had with this species.

I would say with Heterometrus you are far more likely to have a communal set up using young instar siblings than unrelated specimens. They are already used to each other and less likely to turn on each other.

Some species of Heterometrus, specifically the females, can become territorial and hunt down their tank mates. This is particularly true with swamerdammi and maderaspatensis

Personally I have never had a problem with adult spinnifer's together (these were unrelated as well) but they were in a huge tank.

This is something I am interested in as well so I'm building up my collection of various Heterometrus to document communal activity in captivity.

i have a tank with 6 H.petersii and it works like a charm.. allso got a tank with 2 H.spinifer works perfectly allso