6 in a 75 gallon are the perfect mix of dense “shoreline” hiding places on the outer sides with open swimming space in the center. They are very light and flowy, but the vines actually tend to stay where you put them when arranging the plant. They need to be “finger combed” after water changes, to spread them out again after they've bent over from the water level dropping. The bases are heavy and stay in place well, and the vines are neutrally buoyant which is why they seem to stay where they’re pushed. They don’t sink, and don’t float to pull themselves straight. They are very pretty and look more natural after biofilm in the aquarium takes the gloss down a bit.