Hi - got three platties to join my nine cardinals and five gourami - I figure it's at full stocking now so won't be adding anymore. The water parameters are fine, 0 across the board apart from nitrates as normal. There are plants in the tank, and a water filter which bubbles away. I am just a little worried by the platties - they seem to spend a lot of time swimming next to the surface and also going up and down by the sides of the tank.... Any ideas?
