hello im abby from scotland looking for some advice just went from a 65L tank to 125L tank i have two plecos three clown loaches two very big goldfishes and two x-ray-tetras, been keeping fish for about two years and now need advice myself. on why there swimming around erratically and banging against the side of the tank checked ph it was 6.0 and 0.0 nitrate left the lighting off just now and covered the tank,all fish were moved safely and did'nt have any problems to begin with now when the lights are on they freak out