im not sure, they are the smallest of the golden nuggets, id be tempted to say it would be ok in a 190, they do have a fair amount of floor space. i wouldn't have 2 no. if you really wanted you could get 3-4, or more, but you would need a bigger tank, if you get 3, and end up with 3 males, they will fight, maybe not straight away but when they mature a little, they have been known to kill one another. in the amazon where they come from if 2 males bump into each other they will scrap, the winner stays and the loser is never to be seen again, in a tank this isn't possible. you would have to watch 24 hours a day to see if one is getting picked on, or in the case of a pair forming, remove the others, and all other bottom dwellers.
they use wood to help digest their food, but not in any amount as panaque species do, to be honest i haven't had wood in my tank with the gold nugget in for months and it seems healthy, i would suggest having at least one piece of bogwood though.
if you was to have a group i would suggest a set up with lots of wood, rocks and plants, forming ditches most of the length of the tank then it is likely the males (if you had more than one) would use the ditch as its territory, and keep others out of its sight for the majority of the time, in each ditch i would have a couple of caves, just to give a bit of a choice.
you would need to provide one such 'territory' for each plec you decided to buy, it is still very possible you would get fights, you would have to look out for this and remove as necessary. im pretty sure once you have a 'bonded' pair they would be ok together for their lifespan though dont hold me to that.
i must admit a group or a pair of gold nuggets is a beautiful picture to imagine, but would involve a lot of time, effort and patience.
they aint normally cheap so loss's wouldn't be good!
if you was to get a bigger tank, and you wanted to add more, then you should put them all in at the same time, including your existing one, if you see you get one territorial one, remove it, move things around a bit and then put him back, remembering they get stressed easily so take precaution when doing anything involving stress on the fish.
when nearer to the time you get the bigger tank post the thread on here and we will help you, its easier when you have it sat infront of you!
in the meen time get a little bit of bogwood, a nice cave, and make sure the temperature is at least around 28 celsius. and also take into consideration if you want live plants, only particular ones will do well at higher temperatures so do research, or go for ones used in discus set ups!
Dave