I'm interested in pet fish, and I enjoy offering advice to aspiring fish owners.
Newcomers to the fish-keeping hobby will often mistakenly think that it is better to keep cold water fish such as goldfish because they don't require a heater, and the fact that they don't require a heater seems to imply that they are easier to keep than tropical fish.
The opposite is true. Yes, tropical fish will require that their water is kept somewhere between 20–25 degrees Celsius depending on the species, but tropical fish are almost certainly a better bet for the beginner. Why is this? There are several reasons.
1. Cold Water Fish Require More Space
The major reason why I would recommend tropical fish for a beginner is the fact that cold water fish need much more room than tropical fish. A 20-gallon tank is the recommended minimum for just one goldfish, whereas in a tropical setup with adequate filtration, you could have up to three or four medium-sized fish such as Angelfish and a few little shoaling ones like neon tetras in the same sized tank.
Tanks Stunt the Growth of Goldfish
Cold water fish are better kept in an outdoor pond than an indoor one, though you can always raise goldfish and koi indoors for the first few years of life and transfer them over to a pond when they are of sufficient size. If allowed to grow to their full size, even a garden variety goldfish will reach 12 inches in length. Common goldfish types include the common goldfish (obviously), the Comet, the Shubunkin, the Lionhead, the Oranda, the Veiltal, and the Fantail. These are undeniably beautiful fish, but it is cruel to keep them in tanks which stunt their growth.
2. Cold Water Tanks Need More Filtration
All fish types will require adequate filtration, usually in the form of an external or internal filter. Under-gravel filters are being phased out by many fish-keeping stores as they are viewed as being less effective than modern canister, hang on back, and internal filters. Cold water fish such as goldfish are very messy fish and will require excellent filtration if their water is to stay clean.
Clean water isn't just an aesthetic consideration; it is a requirement for healthy fish. Fish wastes are high in ammonia, which is extremely toxic to fish. A good filter system will contain bacteria that convert ammonia into nitrates, and nitrites into nitrates. When setting up a tank for the first time, you will need to cycle your tank, preferably without fish, to build up these bacteria before you put fish in the tank.
3. There Are a Wider Range of Tropical Fish
All fish will also need water that is pH appropriate. Goldfish tend to prefer a neutral pH, while tropical fish have a wider range of pH requirements depending on species.
There are a much wider range of tropical fish species available to the aquarist, and though they do all have their own particular traits and needs, if you are unwilling to go to the effort to monitor water quality, do frequent water changes, and familiarize yourself with the needs of your fish, then any fish is probably not suitable for you.
Whether Tropical or Cold Water, Fish Require Complex Care!
Fish used to be sold as easy care pets, but the reality is that to keep them well, and keep them healthy, they take a great deal more care than your average cat. If you are getting a fish for a child, then be aware that the costs associated with it may actually outweigh those associated with your average family moggy, who simply needs good food, a few vaccinations, flea and worm care, and a warm lap.
Fish require all the following:
- decent-sized tank (not one of those little pet store sold things which are too small to house anything but a few tiny neon tetras or be used as hospital tanks)
- air pump
- water testing kits
- plants or plant substitutes
- décor to hide in
- a whole lot of love and attention
Fish-keeping is an incredibly rewarding hobby, but it also represents a not insignificant investment of time and money.
Rita griffiths on November 20, 2019:
I love my koi and tank fish but the goldfish inside the house are so so dirty so what the best fish to have warm and cold tanks
The Allure Of Cold-Water Fish
Cold water fish, as the name implies, are those that not only survive but thrive in colder temperatures. In fact, there are plenty of cold-water fish who cannot live in warm waters that you normally use to house tropical fish.
Therefore, there are many species of cold water aquarium fish that you can keep in species-only tanks. However, cold water tanks tend to be much cheaper – you won’t have to buy heaters or use up electricity tin order to run the m – and they also tend to be lower maintenance. After all, you won’t have to worry about keeping the water temperatures up!
Furthermore, algae has a more difficult time developing and growing in cold environments. You will need to make sure you clean your tank, still, of course, but you will likely find that your cleaning duties are drastically reduced.
2. Fancy Goldfish (Carassius Auratus)
- Maximum Size: 8 inches
- Temperature range: 65 – 72°F
- pH: 7.0 – 8.0 preferred
- Level of Care: Beginner to Intermediate
- Tankmates: Other peaceful but robust community members.
One of the most renowned of all pet fish – the fancy goldfish is a classic choice for the cold water aquarium. Varieties include Fantail, Ryukin, Lionhead, and many many more.
Whereas common goldfish get far too large and fast for most aquariums, the fancy goldfish has a much calmer and more placid character. Their smaller size makes them a good fit for tanks of 40 gallons or more for a pair, with an additional 20 gallons needed for every extra specimen.
Fancy Goldfish love interacting with each other, and should never be kept alone. Always keep them in pairs or ideally in larger groups to keep them happy. They also really appreciate regular doses of plant-based food, as the animal protein in most fish foods is only partially digestible to goldfish.
Although this fish is a popular choice for first-time fish keepers, Fancy Goldfish will do much better under a high level of care. Proper filtration and frequent partial water changes will make all the difference for this fish – from merely surviving to truly thriving. Well looked after, your Fancy Goldfish could live for over 10 years!