Gasping Koi

Water Garden & Features Q & A

Q: My koi seem to be gasping for breath at the surface of my pond. Why are they doing this? – Bill in Louisiana

A: If your koi are coming to the surface of the pond to gulp for air, they’re doing more than just saying hi. They’re employing a survival strategy! Due to a lack of aeration or poor water quality, your pond’s water probably does not have enough dissolved oxygen in it for the fish to “breathe,” so they’re gasping for oxygen from the air.

This lack of sufficient oxygen can then cause the fish to stress, which then inhibits their immune systems and opens the door for parasites and disease. But you can prevent that from happening by aerating the water and keeping the water quality as crystal clear as possible.

Koi breathe by pumping water over their gills to extract dissolved oxygen from the pond water. Depending on their activity level, koi require varying amounts of oxygen. For instance, a koi’s active summer metabolism will require more oxygen; a hibernating winter metabolism will require less oxygen.

This can be a challenge during the warm summer months, when the pond’s water temperature rises. Warm water holds less dissolved oxygen, so just when the fish need it the most, it’s at a lower concentration!

To pump more oxygen into the water, you can also add plants to your pond, which naturally release oxygen into the water during the day. Your waterfall or fountain will also add oxygen to your pond. But depending on your fish load and pond size, plants and a fountain often aren’t enough – especially during the summer. That’s where an air diffuser, like the KoiAir® Water Garden Aeration Kit, can help. Powered by a silent, reliable compressor, a diffuser system will add oxygen to your pond, aerate, circulate and eliminate dead spots, keeping your pond and fish active and healthy all year long.

Because poor water quality can also cause fish to gasp for air at the pond’s surface, you should also check your filtration system, and test your ammonia and nitrite levels with a standard test kit, like the Pond Care® Master Test Kit. If your levels are high, consider adding beneficial bacteria, like Pond Logic® LiquidClear™, to kick-start your pond’s nitrogen cycle.

Once you aerate your pond and make sure your water quality is in check, your koi should stop gulping oxygen at the surface. When they do greet you at the water’s edge, it’ll be for a juicy slice of watermelon or some Pond Logic® Floating Ponstix fish food instead!

POND TALK: When you see your fish gasping for breath, what do you do?

Picture of String Algae of a Water Garden.

Q: My water garden looked like pea soup so I treated it with AlgaeFix. The product worked great although it took its toll on my fish. My koi and goldfish began gasping at the surface. I immediately did a water change and only lost one small goldfish. I have used AlgaeFix for years and never had this problem. What went wrong? – Lisa of Georgia

A: Oxygen. Oxygen. Oxygen. You must be careful when treating for algae, especially pea green water or planktonic algae. AlgaeFix along with most algaecides on the market work very quickly. When the algae die, they begin to decompose immediately, robbing oxygen from your fish.

How to reduce your chance of fish loss:

#1 – Proper Aeration: Make sure you have an abundance of aeration before you treat for algae. Waterfalls, spitters and fountains all provide aeration. Although, the best source of aeration is generally an aeration system.

#2 – If treating for string algae, remove as much by hand as possible before any treatments. In the case of Lisa’s pea green water, I would have recommend that she do a 10-20% water change approximately 24 hours before her application.

#3 – Get to the root of your problems: Generally ,excessive algae blooms are caused by one or more realistically, a combination of the following: poor filtration, TOO MANY FISH or not enough aquatic plants.

#4 – Use natural products to provide clear water: Although chemicals, when used properly, are a helpful tool they should not be your only solution. For a healthy eco-system and more consistent clear water, turn to a natural remedy such as the DefensePAC and / or Barley Straw Extract.