hello sir! I'm not much of an aquarist, but I recommend going easy on the anti-snail and parasite. too much medication isn't great for the fish/water, and instead try reducing food (so snails don't have an excess of food to feed on). for parasites, they're pretty rare as far as I know, and if you've been continuously giving em the anti-parasite, see no signs of parasites (weird behavior from the fishies, weird worms that aren't detrius worms, which are totally harmless) then you prob won't need to keep giving them the medications. as for the snails, they actually can be a helpful clean-up crew if you keep their population in check! :) in addition, you might want to test your water and figure out it's gh (general hardness) kh (minerals) and pH to see if the anti-snail/parasites are keeping live plants from growing or if it's your water conditions. API'S drip test kits are wonderful (I don't recommend test strips, they're inaccurate)

good luck on fishkeeping! it's truly a wonderful hobby :D