no as far as i no you dont. i dont have fish but as far as i no u dnt have toactually your wrong there, you have to change a goldfish tank alot more frequently then you think i would know because i...
Take a bucket, fill it with water and add dechlorinator. Leave for a few hours to get up to room temperature, then remove the same amount of water from the Goldfish tank, and readd with the new...