First of all the tank is a 160 litre. I have only experience of one other freshwater tank with my Dwarves in and that is still fingers crossed ending its cycle.
1. South American - Probably go for 3-4 with live plants. The teeth trimming does seem a little off putting,but then lots of people keep them and deal with it. I think I would be someone who quivers at the thought but when it comes down to it would just do what is best for the puff (did work in a vet for 2 weeks as experience and had to do some pretty horrid things which thinking back on go ewww now but just got on with it at the time). Heavily planted with easy beginner plants. I have also sourced someone who will prescript Ms222 and also in process of getting snail farm going, these appeal to me as they are the only other fresh water puffs seen and they were too cute and hyperactive, also bonus of freshwater. Worried about pacing?
2. Figure 8 - These were my original choice from way back, kept chopping and changing due to the sixe as quite fancied bigger puff, but then not bothered by this now. Tank would probably be plsatic planted with java moss and fern. Probably go for 3 - worried as they are not as laid back as the SAPs there may be aggression and would not be able to do anything about it.. Salt water no matter how low brackish scares me a little. Normal tank fixtures required with addition of hydrometer and marine salt? Was wondering on another thread it was mentioned about hard water etc "liquid rock" is there an alternative to salt and would this be healthier for the puffs? Also wasn't sure they were as pretty as the others (me being stupid).
3. Green Spotted Puffer - one in the tank though am going to remeasure as thought was 160 but might be 180 - if 180 2? probably not, plastic planted and fake coral. The colours and cute pics of these really appeal to me. The offputting factor is, I am new, brackish and salt water scare me. Also I can not predict the future and worried about getting live rock and protein skimmer later also with the cost of rising salt to be added. (How do you go through a big tub - one a month? The ones i have seen are large tubs costing £20 can not remember the amount). I eventually want a marine tank for a porc so in a way this would be a good learning experience for me. When would be optimum changing to full marine on these, one year, two?
My situation currently, i do not drive puffers in the area are not forthcoming I had to travel for an hour to get my dwarves and locally only seem to be able to specially order in. SAPs are local the other two would be unreturnable. People also don't buy these often in the area. Just to let you know my situation!
