Here I'll give you some of the Ups and downs to the aros you have available to you.
Jardini
Ups
-My personal favorite aro on the account that there are the closest thing any US resident can get to an Asian Arowana, with out smuggling and most likely going to prison.
-Also they very nice patterns on their fins and scales.
-I've heard that many ppl who actually own Jardini say they become quit social pets with their owners.
-They grow smaller than a Silver or Black.
Downs
-They are normally just a bit more expensive than a silver.
-And the main reason why there not the best aro to have, is because they are considered to be the most aggressive species of the Osteoglossids and normally can't e kept with other fishes. Though there are exceptional cases where they can be kept with other fishes with just the possibility there might be a few scrambles here and there. This can (sometimes) be achieved by closely picking tank mate, ans also by how the Jardini's personality is.
Silver
Ups
-Silver Arowana are the most inexpensive aro to perches in the US.
-They are also the most common. (but this really depends on your specific location)
Downs
-One of the huge problems with Silvers is that most of them are captive bred and this then leads to inbreeding and then that causes a week gene pool so that finally leads to many problems with the fish's Phenotype and makes it develop oddly shaped parts such as the most common Down Eye (DE) but I'm not saying that DE is all caused be genetics because there have been reports of Silver Aros developing DE in the wild as well where its almost impossible for them to inbreed out there.
-They are the second largest species of Osteoglossidae, right next to the Arapaima Gigas, thus making them difficult to house without a large and wide tank or heated pond.
Though you say you don't have Blacks available to you I'll still tell you their ups and downs.
Blacks
Ups
-The black's growth and size rates compared to the Silvers is better, Blacks do grow slower than silvers and also grow a bit smaller too, but only just about 8" smaller.
-Also since all blacks are know to be wild caught they don't form many of the genetic defects as their silver cousins do.
-There hasn't been one report of a Black Aro captive nor wild with DE. So that tells us that its mostly impossible for blacks to have DE.
-Most ppl that I've asked who have owned both blacks and silvers say that Black aros are bit more timid and mellow than silvers.
Downs
-Black aros are incredibly expensive though it all depends on the locate the seller, and the size of the fish. in a general aspect the Black Aro are much more expensive than, the Jardini, silver, or the Australian aros.
-One of the problems with Black aros seems that the older they get the more bland they get in color wise.
Australian
Australian or Lei is another common name as well as Spotted arowana are not much different than the Jardini, the only thing is they are just a little less aggressive they have different patterns and spots, and they don't develop the sloping head that the asians and jardini get other than that Leichar Arowana are really no different compared to a Jardini.
I hope this helps you make your decision and if you want to find a black you can find them from some of the vendors and this site such as many ppl get theirs from Nick at N-E Cichlids so you could try him and ask if he could get you one. ~ Red Tail Catking
