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Can You Put Goldfish In Your Horse’s Water Trough

Keeping your horse’s water trough clean is extremely important.  Yet, most of us would rather spend time riding than doing chores.  Finding easy alternatives that help keep water tanks cleaner for longer is an aspiring goal and ongoing issue.

If you ask enough horse owners, someone will eventually tell you that goldfish are the key to cleaner water troughs.  Sounds easy enough right?  Drop in a few fish and you’re good to go. But can you actually put goldfish in your horse’s water trough?      

After doing a bunch of research and actually trying goldfish in real horse troughs, I’ve determined there are a few things you need to know to maximize their potential.

It is possible to put goldfish in your horse’s water trough to keep it cleaner.  As long as you don’t add too many fish and use a large enough trough, they actually do work.  You’ll also need to keep them shaded and add a floating object or rocks in the trough to provide the fish with cover.

There is a lot more to know before you rush off to the pet store, so let’s go over the necessary requirements to get the most benefit from goldfish in a water trough.

Is it safe to put goldfish in water troughs

The question of whether it is safe to put goldfish in water troughs is geared toward your horse’s health and not the goldfish’s.  So is it actually safe for your horse to drink water with goldfish living in it?  The answer is yes, if the trough is large enough so that the water doesn’t become too concentrated with ammonia and fish waste.  

Scientifically, water quality is monitored using a parameter called total dissolved solids (TDS).  Less than 1000 TDS is safe for horses.  Fish help decrease the TDS levels in tanks but may not actually reduce algae levels.  Don’t worry, you don’t actually need to measure this.  If it looks clean and clear, you’re good to go.

Although, adding goldfish to a stock tank does not mean you never need to clean the tank again.  They simply help delay algae buildup and extend the time between when you should deep clean the trough.  

Try to never let your horse drink more than half of the water before refilling.  Ideally, you should be topping off with fresh water everyday or every other day for your horse’s health even if there aren’t any fish present.

And don’t worry about your horse eating a goldfish.  The fish will dart to the bottom out of the way when your horse is drinking.

How to keep goldfish in a stock tank

Goldfish are low maintenance house guests and require only a few basic things to survive in a stock tank or water trough.  However, before you just throw them into the tank they must be acclimated to the water.  Allow the bag you brought them home in to float in the tank for a few hours.  If you want to transition them even slower, add some of the tank water to the bag for another few hours before releasing them.  

You may find that some fish are just weaklings and will die right away.  The ones that do survive will be hardy and can last for many years.

In addition to acclimating your fish, the following conditions will help prolong their lives so they can clean your water troughs effectively.   

  • Fresh water – Goldfish, just like your horse, need fresh water to be healthy.  Don’t go too long before adding fresh water to keep the concentration of ammonia and fish waste down. 
  • Large enough tank – A large trough not only keeps water fresher, it also stays cooler in the summer.  Hot days and sunshine take longer to heat up a larger bin of water than a small one.  Don’t cook your fish in a small tank.
  • Shade – Placing your water trough in the shade will help threefold.  It will naturally slow down algae growth, the water will remain cooler and the goldfish won’t require a floating shade source to protect them from the sunlight.
  • Board for shade – If your tank receives any direct sunshine during the day, the fish will need some sort of shade.  Floating a thin board about a foot long in the water not only gives them shade, it also gives them a place to hide under from birds and other animals. 
  • Rocks for cover – Two or three medium sized rocks stacked in the bottom of the trough will also provide shade and protection for the fish.
  • Don’t use chemical cleaners – Once you add goldfish to a water trough, avoid using chemicals used to reduce algae growth.  Most are harmful to fish.

Depending on where you live, winter months may be too cold for goldfish to survive in stock tanks.  Cold temperatures will also diminish algae growth and mosquito larvae so the fish will not have enough to eat.  It is usually best to remove the fish during the winter months and start again in the spring.

Do you need to feed goldfish in a water trough

The whole point of placing goldfish in a horse’s water trough is for them to eat the debris and algae.  Hence, keeping the tank clean.  They will also eat mosquito larvae if that is an issue in your area.  You should not be feeding them fish flakes.  This will dirty the water faster than if there are no fish in there.

If you find that your fish are dying because there is not enough to eat, decrease the number of fish.  Your tank may only require one or two fish to keep it clean while providing enough for them to eat.

How many goldfish for a water trough 

The number of goldfish that you can put in a water trough depends on the size of the tank.  In general, you can have one fish for every 20 gallons of water.

You can safely put more fish in a bigger tank.  However, you do not want to create a situation where too many fish are causing dirty water for your horse to drink or there are too many fish for each to get enough to eat. 

The following chart shows the maximum number of goldfish per gallon of water for a water trough or stock tank.

Remember, you will not be supplementing feed for these fish so even though there is enough water to support the maximum number, there might not be enough natural food for them to feed on, especially right after deep cleaning the trough.

Gallons of WaterMax Number of Fish

You can always start with fewer fish and add more later if needed.

What is the best type of goldfish for water troughs

Goldfish for water troughs don’t have to have fancy tails and beautiful scale patterns.  Common or “feeder” goldfish varieties will work just fine.  And let’s face it, you aren’t going to want to spend a lot of money on expensive fish before you know if they are even going to work well or survive.  Your local pet store should have common gold for less than $1 each.  

Do goldfish actually help keep a water trough clean

Some horse owners swear by goldfish and others say they cause more work than necessary.  Multiple factors besides just fish come into play when trying to keep a water trough cleaner for longer.  

A recent study done by Devan Catalano, PhD, with the University of Minnesota comparing goldfish cleaning abilities in metal vs. plastic stock tanks shows that both tank types were very comparable.

The goldfish ate more total dissolved solids and keep the water clarity and algae levels slightly better compared to the tanks without fish.

She also noted that horses are not picky about which material is used, they will drink from both galvanized and plastic tanks equally as long as the water is clean, regardless if goldfish are present. 

Based on the study’s results, galvanized tanks do remain cleaner longer than plastic ones.

The bottom line

Goldfish are not harmful to your horse if the water stays fresh and in terms of cleaning power, they might be beneficial in certain situations.  However, as a responsible horse owner, you are still going to have to scrub your water tanks by hand.  And you might find that having to catch and re-acclimate fish every time you clean the tank isn’t worth the few less passes with the scrub brush.    

There are better ways to keep clean, fresh water for your horse.  Be sure to check out my comprehensive guide on how to clean your horse’s water trough.