Cold Water Fish Guide: Who’s Who?

Cold water fish don’t always live in cold waters, the name can actually be a little misleading as they tend to just not need a heater in their setup. Cold water fish actually live in room temperature tanks so you don’t need to maintain a heater but you also don’t need to find a solution to keeping your water cool either. They tend to be quite hardy species that can tolerate lower temperatures in Winter. They usually prefer temperatures of around 20°C or lower which is perfect for unheated tanks in the British climate!

Some cold water species may come from warmer climates but have evolved to withstand a range of temperatures to live in. Warmer water fish will fail to thrive or possibly even die if housed outside of their preferred temperature while cold water fish will continue to thrive if everything else in their aquarium is well-maintained. It might go without saying but cold water fish and those that prefer heated tanks should not be mixed as the warmer water fish can’t withstand the temperature that cold water species can thrive in.

You might assume that cold water fish will all originate from cooler climates but that isn’t always the case. For example, the most common cold water fish is the goldfish which we can trace back to China. They were first kept in ponds and bred for their magnificent variation in colours but they’re hardy fish who can survive in a variety of different environments which suited the hobby breeders of the 17th century.

While they might have originated from a country with a warmer climate, they don’t need the warmer water to thrive. Similarly, the white cloud mountain minnow are from China as well but their ability to tolerate lower temperatures benefited them to make them able to thrive in even the harshest environments where other fish could not. Most cold water fish are not from a specific place but rather, they have evolved to be able to live in the less hospitable waters of those areas which can often get cold.

One thing cold water fish have in common is that they don’t need a water filter but every other aspect of their care can vary. Not all cold water fish can live together so when deciding what to stock your tank with, keep that in mind. Many cold water species will be limited to a single species tank or might need to live with similarly sized cold water species who prefer placid temperatures.

Goldfish are a very common species of fish kept throughout the UK and historically, have dealt with more than their fair share of inhospitable environments. From being given away as fairground prizes, which is now against the law, to being housed in tiny, inadequate bowls, they have known struggle in their domestication. Being able to live in these environments for several years at a time shows just how hardy this species is. However, goldfish do need a lot of space to thrive. While they are happy to be kept at around 18 to 22°C and don’t need a heater, they do need a minimum of 60 litres of space per individual to be comfortable. Goldfish are a messy species so when housed in smaller tanks they need regular cleaning to manage the nitrogen cycle.

Goldfish will try to eat other species of smaller fish and they also like to eat aquarium plants so may not be suitable for a heavily planted tank. On average they will grow to about 15 to 25cm in length but have been known to grow larger when given the ideal environment to thrive in. They tend to feed at the surface right down to the middle of the tank so a high quality goldfish flake is best for them. On average, goldfish can live between 10 and 15 years if well cared for.

White cloud mountain minnow might just be the most hardy species of fish you can own. They’re a great choice for first time fish keepers who want to watch a school of fish thrive in their cold water aquarium. They do well in temperatures between 16 and 24°C but if it’s too warm, they will start to get stressed. As a schooling fish, the white cloud minnows prefer to live in groups of at least six which will require a minimum of a 39 liter tank to explore. They can live in heavily planted aquariums so if you’re a fan of aquascaping, these are a great choice. They are also a peaceful community fish that do well in tanks with several different species as long as they don’t get bullied.

The white cloud mountain minnow can reach about four centimetres in length and in their natural habitat mostly eat plankton, but in tanks will take flakes, pellets and even smaller foods made for fry fish and small species. They might look unassuming when you bring them home but when they get a chance to destress, they’ll get a gold sheen across their bodies and red-tipped fins.

Zebra danio are closely related to white cloud mountain minnows and from a similar environment. They thrive in temperatures between 18 and 24°C so while they don’t need a heated tank, they do need a little more free swimming space than the minnow. They prefer longer tanks of 39 litres or more to have plenty of swimming space and need to live in groups of five or more. While they need plenty of space to swim, they also need enough coverage to feel safe enough to do so. Danios are most active at the top of the tank so some floating plants can help them feel confident enough to show off their natural behaviours.

Zebra danio got their name from the gorgeous stripes along their body which look especially eye-catching when they are schooling. They can be fed flake food but since they only grow between two and a half centimeters to an inch, it may have to be crushed up smaller so they can eat it. They can live up to five years in an aquarium and are another species well suited to new fish keepers.

The rainbow shiner is a species of minnow originally found in Alabama. They are just as hardy as their white cloud cousins, if not even more so as they can thrive in temperatures from 10 to 22°C. They are a peaceful schooling species but as they are a larger species and can grow up to three inches in length, they do need a tank that is at least 90 litres to house a minimum of five but do best in groups of ten or more. They spend their time around the top and the middle of the tank so floating flake food is great for them. Rainbow shiners can be quite shy so prefer a planted tank with lots of places to hide.

They got their name from the stripes of red and blue that run along their whole body with areas of iridescent colour that are spectacular when schooling together. With good care, they can live between three and five years. They do well in community tanks with other peaceful species like danios to keep them company.

Originally from Mexico, the sunset variatus platy is a schooling fish that does well in groups of five or more. They can thrive in temperatures between 16 and 24°C so they don’t need a heater as long as your house is kept relatively warm through the Winter. They are brightly coloured and come in a range of different varieties with the males being more spectacular to look at. They are easy to breed but if you’re keeping a mixed sex tank, you’ll need several females for each male to make sure they don’t get harassed. The variatus platy can grow up to seven centimetres in length and will need a tank that is at least 39 litres.

They can eat a range of foods including flakes, granules, algae wafers and pellets so they really aren’t fussy with their diet. In their natural habitat, they tend to live in heavily planted ditches or springs so they enjoy a good amount of plant cover. With proper care, they can live for up to three to four years.

Even without installing a heater, your options for filling your aquarium with interesting and beautiful fish are not too limited. For all of your fish necessities when setting up your cold water tank, visit us in store and online for some great deals.