Beginner Care Guide of Koi Fish

Date Posted: 2023-02-01 17:30:15

Common Name: Koi

Scientific Name: Cyprinus carpio

Average Size: 15 -90cm, varies with breeds

Life Span: 10 – 35 years with proper care

pH: 6.5 – 8.0

Temperature: 23°C – 30°C

Water Hardness: 5 – 12 dH



Koi are omnivores. They consume plants and animals matter in the form of pellets, freeze- dried, frozen or live food.


After some time, koi may recognize their owner and may take the food directly from owner’s hand.


In generally, koi are peaceful species but may pick up small fish slowly.


Pond size:

Koi are big fish and fast growing fish, so it is better to keep them at outdoor pond. Generally, 228 litres of water for each koi is needed. Depth should be at least 2 – 3 feet for koi to hibernate and seek refuge.


Koi are a type of fish that like to dig. Therefore, it is better to protect the root of plants with a layer of gravel. Fertilizer ball like JBL 7+13 Ball which provides sufficient nutrients are recommended to promote healthy plants growth and not algae. Floating plants can be added a well to create shady areas for koi.

Water Temperature:

Maintain the water temperature to between 18°C – 30°C although they can tolerate cooler water temperature.

UV Lighting:

Set up the UV light system by installing JBL ProCristal UV-C to aid in the battle against floating algae and infectious germs in the pond water.

Pump and Filter System:

Install an appropriate filtration system according to your pond size will ensure good water quality. Aquael Maxi Pond Filter and etc. are good choices.

Water Change:

Advised weekly change 20% of pond water, at least 40% of pond water monthly.

General compatibility:

Goldfish, other koi, loach and bottom dwellers such as Plecostomus.


Staple diet:

High quality of koi food from JBL Propond All Seasons and Tetra Pond Koi Stick promote a healthy digestion and koi’s nutritional requirement.


Essential amino acids like JBL Atvitol can be added together to their food.


Koi are aggressive eaters. Feed ample amounts 2 – 3 times daily with no more than they can consume in 2 -3 minutes.


Sign of healthy:

- Clear eyes

- Smooth and clean in appearance

- Eat vigorously

- Calm and steady gill movement

- Bright and even body coloration

Sign of illness:

- Loss of body coloration or appetite

- Lying on the bottom of pond

- Poor growth or weight loss

- Fins clamped to sides

- Scraping body on rocks

If you notice any illness sign(s), please to test water quality and improve it if necessary.


- Avoid fish pond from being overcrowded as it may cause stress to fish and higher chance for them to get sick.

- Regular water change and an appropriate filtration is needed to maintain a good water quality.

- Check water quality by using JBL Test Kit at least once a week.

- Wash hand with soap after each time handling your fish pond.