Weeksii activity level compared to others

So I have kept bichir for only a short period of time but find their activity levels are very different depending on what type you have. I get a lot of activity from my Del and Albino Sen but almost nothing from my 'gold dust' or weeksii.

So a question for you bichir keepers.

Will I see an increase of activity from the weeksii as it get older?
(currently it is 9" with external gills still showing, was wild caught and Ive had it for months and still trying to pellet feed it)

Or is this typical behavior for a weeksii?

Should have added some info:
Tank is a 72g bowfront with an AC110 and Eheim 2217. Yes I know how big Weesii get and I already have a 210g set up for him

Tankmates include: 8.25" Delhezi bichir x1, 6.5" Albino Senegalus x1, 4" Gold Dust Polypterus buettikoferi x1, Australian Rainbow x 6

I have been trying to pellet train him on Hikari Sinking Carnivore, 6mm NLS Thera and feed tilapia and baitshop nightcrawlers. He will eat the real foods but not pellets even after weeks of a strict pellet only diet.

So maybe its just not the right one for me?

Here are a few pics from when I first got it

I almost wished I went with an Ornate instead. But when I was researching I read that the weeksii were more 'mellow' and basically played well with others. This was important because the 210g is extremely peaceful with a large Pearsei and a school of red hook silver dollars. The ornates have a reputation of being more active but also can be a bit more aggressive.