It doesn't matter what size tank it is. The Jardini and silver will end up fighting until one dies. It won't work. The only way it could ever work (it's a possiblity) is if you buy a silver and jardini as babies and raise them together.
I think Silver Aros look so much more... graceful? They are also more peaceful, and they have that sleeker, more ancient look to them. To me, a Jardini is just a really ugly and cranky silver. Just my $.02, and I'm sure there are plenty of Jardini fans out there who really love their fish.
The problem here is that if i did buy a Silver,then my 2 Aro's did fight and i had to bring the Silver back i would lose all that money,my local LFS doesnt give money back or credit anymore.
Here is what i consider the good and bad sides of both fish;the Silver is sleek and gaceful looking,it is also alot more peaceful,but they are vey skittish and will jump on impulse,the Jardini is kinda rare(especially around here)they get a massive build to them when fully gown,they arnt really as skittish and tend not to be so jumpy.But it is very hard to keep them with any tankmates(i am lucky i guess)they can be mean and hornery.I actually like both builds of these 2 Aro's,but i guess i r eally am leaning towards the Jar because they are not so skittish and jumpy so yup i'm keeping my Jar.
i would go silver only because a single species tank can get very boring.
and the catfish will most likely end up dead eventually.
I have 6 silvers over 24 inches and they are more interesting to me to watch.