When it comes to pond fish, the most popular choices are goldfish, (which need no introduction) and Koi, (a Japanese carp). Both are beautiful and well-adapted for pond life. However, there are differences between the two that should be taken into consideration before a final purchasing decision is made. This article will discuss these differences in more detail.

Firstly, when it comes to size, goldfish are smaller than Koi. For this reason goldfish should be considered if a person has a pond size that is 50 to 500 gallons. If a pond is bigger than 500 gallons, Koi are the better choice. In fact, since these fish can grow immensely, the larger a pond is the better if a person does invest in the Koi.

Secondly, when it comes to general care, goldfish tend to be much easier. This makes them the perfect choice for a person that is new to pond ownership. On the other hand, Koi should be reserved for a pond owner who has more experience. This is because due to the size of the Koi, they require a greater amount of water. If they do not have enough water, wastes accumulate, which could make them get sick.

Thirdly, a pond owner needs to consider the plant life within their pond when deciding between goldfish or Koi. Generally, goldfish do not bother any plant life that is placed within the pond. The most they may do is play with lily pads. Yet, Koi like to dig around plants, creating quite a mess.

So, if a pond owner has Koi, they will need to decide how they are going to deal with their potted plant situation. They could opt not to have them at all, which is the easiest alternative. However, some pond owners may insist on using potted plants. In these cases pond owners will need to consider additional options. One could be placing a net over the pot. Another option involves placing one inch of pea gravel on top of the pots. Koi cannot dig through netting or pea gravel.

Fourthly, the Koi species of fish are cold-water. Pond owners will need to keep this in mind as they are caring for them. This means making sure there are deeper areas within the pond to accommodate for season changes. Specifically, during warm weather these areas should be around 1 meter deep, while they should be about 1.5 meters deep during colder weather. The areas need to be deeper during colder weather to prevent freezing.

Lastly, there is the issue of longevity. Goldfish can live up to 20 years, while Koi live a minimum of 35 years. Koi have even lived up to 200 years, though this not as common. Regardless, this 15 year difference in life expectancy should be considered, since it means 15 more years of not having to worry about fish replacement. However, if replacement is not as much of an issue, goldfish are a better alternative since they are much cheaper than their Koi counterparts.