They are colourful, peaceful, and have a long lifespan. These fish can and will grow up to 15 inches or more. This many fish in your 19 litre are a disaster waiting to happen. Your fish sound like common goldfish, the one with the longer tail is probably a comet. The common goldfish can grow up to 30cm long. Depending on breed, goldfish can grow to 10 to 20cm. = Medium fish stocking - Pond with plants and total fish length of up to 800mm* per 1,000 litres or Light Koi/Turtles with a total length of up to 400mm* per 1,000 litres = Heavy fish stocking with a total length up to 1000m* per 1,000 litres or Medium Koi/Turtles with a total length of 500mm* per 1,000 litres This means that depending on how many goldfish and what length they are,the size of your tank may differ. A pond with 500 to 3000 plus gallons of water is good to hold fish. Fish can make good pets but buying a fish should be a long term decision as they can live for up to 20 years. That means that one 30cm goldfish would need a 132 litre fish tank just for themselves! This method for estimating how many fish a tank can support is superior to the traditional a "how many fish per gallon" or "per litre" rule of thumb, such as "one inch of fish per gallon" or "one centimeter of fish per litre". ... (liters). Smaller fish like White clouds, guppies or galaxias can be kept in denser numbers. The second rule of thumb is to allot 1 square foot of surface area per inch of fish and 10 square feet of surface area for 1 … This is a general rule I use mostly for gold fish, which is the most commonly sold pond fish here in Australia. They will need a very very large tank or ideally a pond. Hey, my long career as a geek fishkeeper started with two goldfish in an unfiltered 25 litre tank (in my defence, I was only 6), it's how everyone starts! A goldfish that is properly cared for can live for well over five years (40 years plus max) and grow to around 12 inches long, 32cm (4 inches average, 10cm).A small one-gallon goldfish bowl (3.7 liters) is not highly recommended. Also bear in mind that as your goldfish grow you will have to upgrade their tank to give them enough space. The goldfish diet should contain a high carbohydrate level. Any freeze-dried food should be soaked first to avoid digestive upsets. ... A single fancy goldfish needs a minimum of 75 litres and then an additional 35 litres per additional fish... A comet needs a minimum of 150 litres with an additional 50 litres per fish according to manyreputable aquatic community sites. Depends which part of Australia you live. Make sure you enter the actual water depth and NOT the aquarium glass height. Anything smaller should avoid fish keeping. Water in Townsville is deadly to fish if not treated for chlorine. 48 litres is way better than 14 but still won't last them long. If you can provide 50% water changes daily you may keep them alive for a while but they are grossly overstocking your tank. Step 2 - Enter the Internal measurements of your aquarium in centimetres into the corresponding blank boxes provided as per the illustration. If you want to keep your goldfish, which are probably common, you need to get as big a tank as possible. If you want your goldfish to live a very happy life (I want them too) you should be looking at a 100g tank with 1000g per hour filtration. It is important to avoid overfeeding goldfish as this can cause indigestion and/or contaminate the tank. Allot 35+ gallons per inch of koi, and at least 20 gallons per inch of goldfish. How many goldfish can fit in a 20 litre fish tank cold water fish. Instructions for use: Step 1 - Choose the Tank Shape. Feed 2-3 times daily. Select Rectangular, Cube, Corner, Cylinder or Half Cylinder then click the "Update" button. When you place a goldfish in a small space like a bowl, the water gets dirty fast and make the goldfish unhealthy. ÷ 3.785 liters(per gallon) 7.3976221929 total gallons. reply #6. Slender fish such as tetras or danios use less oxygen than full-bodied fish such as goldfish or … Goldfish are one of the most common fish species kept as pets. I personally like to allow 100 Litres (40gal) per goldfish. Let’s say 4-10 fish per 100 Litres.