Hi there
there is no problem keeping archerfish in freshwater. I have been keeping them in totally freshwater for years. Presently I have 12 Toxotes chatareus that I have had for 3 years, 5 T. lorentzi and 3 T. jaculatrix that I have had in FW for two years.
They are a very hardy and tolerant fish, provided you do not disturb them too much, they do not like being caught in nets and do not like being moved between tanks. If they get disturbed at night or even during the day they have tendency to take off at high speed and break their spines on the glass walls of your tank. To reduce the chance of such injuries always move slowly and methodically when around their tank and try not to create loud bangs/vibrations that might startle them.
They do tend to form social heirarchies within the tank when more than one archerfish is present, which can make feeding problematic, try to ensure that all fish get equally well fed, I accomplish this be putting food at both end of the tank at once or spreading it widely if there are more than two fish.
They do not need to be fed often, I feed mine about once every week or two. They will eat most anything from live fish, shrimp, crickets, worms, grubs, to frozen shrimp, blood worms, to dry pellets flake and even meat mince.
Enjoy.
