I have a small tank so i can only have so many fish. really, the only things in there is an albino pygmy corydora(they’re a super tiny variety my local fish store has, mine is fully grown and about 3/4 inches.) and i have two platies as well. i know i can add some shrimp and all that but the shrimp i bought from that place in the past died the next day. the only other options are petsmart and petco, but my petsmart has worse fish then walmart and petco only sells bamboo shrimp which i’m not looking for. and i refuse to buy animals on the computer. so in my tank i n noticed its empty. i have like 1/2 inch of gravel(i know i should have sand for the corydora but i have round edged and i heard that’s ok) and three plastic plants, two small and a medium. i also have this dinky little decoration of a seashell with barnacles on it. I don’t have enough gravel to weigh my plants down sometimes and they will float to the top and you ca See the little plastic stands even when i pushed them into the gravel all the way. so basically what i want to do is go out and buy maybe an extra 3 pounds of gravel and like 2 or 3 larger plants to create a background-of-sorts and buy a medium sized decoration or some driftwood. i want to create kind of a hiding space for the fish if they want some privacy. thing is though, ive had this aquarium up for 6 months now(its my second one) and its cyclled and everything. obviously im going to need to do a 100% water change to do this. but then wont this destroy all the bacteria on the plants and gravel? thing is though, i bought a tetra chemicals kit today(it was on clearence, it was 25 dollars originally and i got it for 6. beyond a steal.) and it came with some of that safe start stuff that adds the bacteria to the tank. should i use this if i do do this thing?