ive had fish pretty much my whole life (parents took care of them until i was responsible enough.. same as most people i guess lol) that being said i know very little about past.. sifon gravel, change 30% and put a few pinches of food in lol

ive had this tank for about 5 years and was populated with like 12 fish (mostly different tetra) they died off one at a time over the years so last week i decided to break the tank down and replace everything, gravel, plants external filter.. everything

the fish i had left was 2 neon tetras and a ridiculous 13 inch pleco

ive since 3 Australian rainbow fish, 3 dalmatian molly, 3 Opaline Gourami, 2 zebra danios, and an african dwarf frog just because ive never had one

i have a 35 gallon tank and the pleco is 13 inches and from what i understand he could get quite a bit bigger..is he too big? hes been in it for like 3 years now and and seems to be fine.. but ive heard they need atleast 55 gallons and i have a 55 gallon tank in my garage that i would rather not use simply because it weighs a ton and would take some serous rearanging of my room so if it is bad for the pleco to be in a 35 ofcourse ill spend the 4 hours it will take setting it up but if not ill keep him in the one i have so is it cruel to keep him in such a small tank?
and does the "fish only get as big as their environment allows" apply to plecos? it doesnt seem to lol

and i know how everyone feels about petco and petsmart and i definitely dont trust them with my snake but the guy at petsmart told me not to use freshwater aquarium salt and the guy at petco said its the number 1 thing he would recomend for a tank with new gravel, water etc. so aquarium salt yes or no?