How many cold water fish can I keep in a 7 gallon tank (27litre)?????
I would not go by volume of the tank but the surface area and the temperature of the water. The warmer the water the less oxygen that the water will contain and the smaller the surface area the less oxygen the water will take up. A tank 24″ x 12 ” will have two square feet of surface area and at 15C I would say this tank has enough oxygen for up to 4 gold fish and no more. A tank 24″ x 12″ x 12″ is 2 cubic feet which is 12.5 imperial gallons or 16.6 us gallons, 53 litres. The white slime on the blackmoor was probably the skin reacting to chlorine in the water which should be allowed to evaporate or removed before adding any fish. Hope this helps. I own a pet and aquatic store, how to set up a tank and cycle it is available free on my web site.
