Newbies just entering the hobby might get confused about whether to set-up a cold water fish tank or a tropical fish tank for their first tank. While both tanks are relatively easy to set up and maintain with proper knowledge and care, there are some fundamental differences that need to be addressed before proceeding to the tank of your choice.

Coldwater fish in terms of the aquarium trade refers to any fish species that prefer cooler water temperatures. The optimal temperatures for these fish hover around the 68-degree mark, although each species’ temperature range may vary from the norm. The main take away message is that cold water fish like cooler waters compared to their tropical fish counterparts. Typically, these fish can survive at even lower temperatures for a period of time. The most notable fish species that you will see in chain stores that fit this category would be Koi, Goldfish, Zebra danios etc.

The main advantage of going with a cold water tank is that you shouldn’t need a heat source for your tank. This one key advantage might sway many of you to go this route. However, there can be some disadvantages to going this path compared to sticking with a tropical tank.

Coldwater fish tend to be less colorful compared to their tropical counterparts. Of course, beauty is in the eye of the beholder and everyone has different taste. But, as a whole tropical fish have a lot more of variety compared to cold water fish.

The more common types of cold water fish that are easily accessible to the majority of consumers tend to require bigger tanks and aren’t suitable for nano tanks. Goldfish, for example, require a lot of room as they grow much bigger than people expect. Koi and Goldfish are more suited for an outdoor pond or at least a tank that can properly house them. Along with this, these fish species have a longer lifespan compared to other fish. This might be a good or bad thing depending on if you are committed to take care of them.

There are some cold water fish species that can be suited for a nano tank. However, many of them require special care. Take for example the pygmy sunfish. This fish stays relatively small and can do great in a small tank as long as you have a species only tank and know how to take care of them. These fish are harder to come by and require live food.

Tropical fish refers to fish that are kept in heated aquariums. These fish species need higher temps ranging from the high 70’s to 80’s in some cases. Fish in this category are a lot more common in the aquarium trade and easily found in pet stores. Some notable examples would be Betta, Guppies, Cichlids and many others. The main requirement for these fish is a source of heat. Whether it be from a submersible heater in your tank or keeping your fish room warm, it doesn’t really matter as long as you can maintain the temperature in these ranges.

Tropical fish, for the most part, need a reliable source of heat for their tanks. They come from waters that are naturally warm and don’t do well in temps that you and I might find comfortable. A submersible heater is one option that many hobbyists use to reach those desired temperatures. However, it’s not uncommon for some of these heaters to fail after so many years of use.

This added risk factor is something aquarists should be aware. When choosing a heater make sure you do your homework and don’t be afraid to shell out some extra cash for a more trusted heater. If you house many tanks having a heater in each tank might not be an option. In this case, I would recommend making a fish room and possibly just heat that one room at the desired temperature.

Aside from tropical fish needing a heater, there are many advantages tropical fish have over cold water species. As stated before, tropical fish are much more easily obtained compared to their cold water species. A lot more species are suited for the nano scene due to their smaller sizes, and their color schemes can range over a huge gamut of hues.

Either route would be suitable for your tank. Just make sure to know that not every fish species falls into single categories. Like, people, there are always exceptions to the rules and it’s up to us as aquarists to make the right choices for our fishy friends. Remember, there are a lot more steps to go from here in determining what a tank needs to be suitable for your fish. Always be sure to do adequate research before committing yourself.