How many cms per litres of water

[radu]

Hi

Can someone please let me know what is the rule of thumb when it comes to how many goldfish per litres of water. I have a 205 litre tank and have two 17 cms long gold fish, one 16 cms long fish and 2 x 10 cms long goldfish. Would like to put in two more 16 cms long goldfish but not sure if I am overstocking. Have a Fluval 304 filter running in the tank.

Thanks

[Caryl]

Litres isn't as important as water surface area. General rule is to multiply the length by the breadth of the tank (in cm) and divide the result by 76. This will give you the total cms of fish you can keep.

eg. my tank is 120cm x 50cm so = 6000. Divide 6000 by 76 = 78.9 so the total I could keep would be 78.9cm.

You already have a total of 70cm of fish and your tank is possibly smaller.

Other things to make a difference are the amount of filtration, the tank maintenance, and the size of the fish. As fishes get bigger, so does their resultant waste, and goldfish are very messy. I think your filter is probably just coping with the current load and adding another 32cm of fish is asking for trouble.

[mustcooktea]

Hi radu

I agree with Caryl in regards to surface area and I know that was a motivation for your new tank. Another general rule that I have heard for fancy goldfish is one for every 10 gallons (approx 38 litres). This is for full grown fish like yours (I think 6 inches not including the tail). That would mean that you could keep five fish in your tank with good filtration (10x per hour). Above that and you would need extra filtration and extra water changes.

MCT

[radu]

Hi thanks for the info, yes you caught on quite well about the reason for me increasing the size of my tank. The Fluval 304 is meant to filter up to 300 litres tank water, so I have over compensated by getting a filter that filters more water than I have (205 lites) I was actually told to get this filter by the Fluval rep as he was in the shop when I bought everything. I do 25% water change weekly.