Hot Tub To Fish Tank Conversion

It is usual for an old hot tub spa to be added to the millions of wastes in landfills. But little did people know that they can be recycled into a usable product that can help people save money.

If you are planning to raise a fish of your choice in your yard, it is a good idea if you keep your old hot tub spa at home.

A Must-Read: Top Fishing Accessories

How to use an old hot tub for raising fish? A hot tub spa can work just like a typical hard plastic pond liner shell that most people buy to develop a pond.

In order to make it work, you will only need a soft liner to prevent algae from flourishing by protecting the jets.

In this short read, I will give you an idea of how to recycle an old hot tub spa into an ideal environment for raising fish.

I will also discuss how to form the right fish ecosystem to allow fish to grow and reproduce.

Converting An Old Hot Tub For Raising Fish

With new plants and other landscaping tools, you can turn an old hot tub spa into an impressive pond where you can raise fish. It can look like a natural garden pond made with a traditional hard pond liner when used in the right way.

You have to dig a large hole in your yard or garden. It is where you will place the hot tub, but before doing so, ask the utility locator service to determine the safest spot where you can dig.

To proceed with your DIY hot tub pond project, here are some of the things you will need to convert old hot tub:

  • Bleach
  • Garden Hose
  • Digging Tools
  • Landscaping Spray Paint
  • Scrub Brush
  • Masonry Sand
  • Rubber Pond Liner
  • Blocks, Sand Bags, Rocks
  • Stones
  • Pond Plants
  • Pond Filter & Pump

Assuming that you already have these things with you, follow the step by step guide below to turn an old hot tub spa into a garden pond for raising fish:

Step 1: Clean The Hot Tub

Your old hot tub needs a makeover. The first thing it needs to go through is a tough cleaning with the help of a scrub brush, bleach, and detergent.

Grab that scrub, then start removing the algae and dirt that has flourished in the old hot tub. Afterward, remove stains and bacteria from the spa using a diluted bleach solution.

You can make this cleaning solution by mixing one part bleach with nine parts of water. Let the bleach solution sit for a few minutes, then rinse it thoroughly with water to eliminate all the bleach residue.

Make sure that the hot tub is free from any bleach or detergent residue before drying. Bleach and detergent contain chemicals that may risk the health of your fish.

Step 2: Trace The Edges Of The Hot Tub

Now that you have a clean hot tub lay it upside down on the space in your yard where you want to install the pond.

If you are wondering why you need to do this, you can trace the edges of the hot tub using landscaping spray paint, creating a mark on the ground.

You will use the marks to ensure that you dig in the right area during the next step. When done marking, grab your shovels and ask a friend to help you start digging.

Step 3: Dig A Large Whole

In this step, you will need the help of some digging tools such as a shovel.

Make sure to follow the mark that you made using landscaping spray paint in the previous step in digging a large hole to fit the old hot tub.

Also, take note that the depth has to be about 1 ft. deeper than the hot tub’s depth. The hot tub’s lip can rest parallel to the ground when it is placed inside the hole.

This step is so much easier when you use heavy machinery. On the other hand, you can dig it on your own using a shovel with the help of other hand digging tools.

Step 4: Place The Masonry Sand

After digging enough hole where the hot tub spa fits, line the hole’s bottom part with about 12-inch of coarse masonry sand.

It helps to provide a firm and robust bed that features good drainage to keep the hot tub in place.

Step 5: Place The Hot Tub In

Now that everything is set to place, the old hut tub inside the hole filled with some masonry sand.

Afterward, put clean soil around the hot tub’s edges to fill in the 12-inch gap around it. But before doing so, make sure to remove debris and rocks to avoid damaging the hot tub.

Step 6: Place Sand Bags, Blocks, Or Rocks Inside The Tub

You can use sandbags, rocks, or blocks to decorate the surroundings of the hot tub. These materials can create different dimensions in your new garden pond.

And if you wish to put some plants in the tub, these materials can support them. You may also use blocks, sandbags, and rocks to vary the water depth inside your DIY garden pond.

Step 7: Put A Rubber Pond Liner

After giving your garden pond a varying depth, it is time to lay a rubber pond inside the hot tub. Press it out to conform to the sides of the tub as well as any component inside it.

However, let about 12 inches of the rubber liner overlap the edges of the garden pond. Let the extra material rest on the ground that surrounds the pond.

Step 8: Add Natural Stones Around The Pond

You wouldn’t want the pond liner to be visible. For this reason, you should place some natural stones around the corners of the pond to keep the rubber material hidden.

The rocks may rest on the hot tub’s lip to cover the edge. Afterward, trim the excess rubber pond liner outside the rock border.

When done, observe if the hot tub’s edges are entirely concealed. You can also add more rocks according to your preference, as well as plants to the soil that surrounds your DIY garden pond.

Step 9: Fill The Hot Tub With Clean Water

You are almost done with your DIY hot tub garden pond! To begin raising the fish of your choice, fill the pond with clean water first.

Start by connecting a submersible pond water pump and filter. Allow the pump to submerge underwater to circulate and purify the water.

Afterward, let the pond plants to sink underwater. Let the pots rest on the shelves that you have created just below the pond liner.

When finished, you are ready to raise fish in your first DIY hot tub garden pond!

A pond that is filled with water that came from the city water supply may arrive with high-levels of chlorine.

It might be required to make some adjustments or wait for a while before adding the fish and other living creatures in your garden pond.

It is also ideal to purchase a testing kit at spa and pool centers to know the chemicals resting in the water. Also, you can install the hot tub just like an above-ground pool by following its height.

This option is best for those people who do not want to dig a huge hole in their yard.

A Step By Step Guide To Form Fish Ecosystem

After converting an old hot tub into a garden pond, you may also need to prepare the right ecosystem for raising fish. You can follow the same steps, whether you are fish farming in a different kind of fish pond.

Leave The Pond Water Untreated

After filling your garden pond with water, leave it untreated. Do not mix chlorine and other chemicals that may prevent helpful organisms from thriving in the water.

Add The Fish Of Your Choice

When filling the garden pond with untreated water, you can begin adding the fish you want to raise. Some of the best fish you can grow in a garden pond is the following:

Carp Or Koi Fish

Among the most recommended fish to grow in a garden pond is a Koi or carp.

These fish species are known to be very resilient and ideal to grow and in places that experience extreme weather conditions.

Aside from that, they can grow into a large size too. Koi fish also eat vegetables, fish food from stores, fruits, insects, cereal, and many more.


Another option you can have is trout fish. This fish is ideal for those people who are living in cold places. They are very resilient to extreme cold conditions but a little bit challenging in terms of feeding.

You may find yourself without a choice but to feed them with commercial fish food.


A lot of fish farmers are raising tilapia in their yard. This fish species can thrive in nearly any type of weather condition.

Still, they require water with a temperature of around 77 to 86 degrees Fahrenheit.

For this reason, you will need a water heater when the temperature of the water drops below the given stats. If you have a water heater, there is no need for you to worry much about it.

Add Feeder Organisms And Urine

The last step to having a ready ecosystem for raising fish is to add feeder organisms as well as urine in the pond water.

If you are wondering why urine is necessary for this step, urine works as a fertilizer that neutralizes the water.

You can use different kind of feeder organisms that is easiest to access in your area. These feeders still provide the same effect in your garden pond.

Benefits Of Having A Garden Pond For Raising Fish

Raising fish in your yard offers a lot of advantages. Know each of them below:

Know Where Your Food Came From

Among the benefits of raising fish in a garden, the pond is you’ll know where the food you eat came from. You can choose what plants grow around your pond as well as the food your fish eat.

For this reason, you will be confident that the fish you and your family consume is safe and nutritious.

No Chemicals Used

If you raise fish in your garden pond, you will be able to ensure that no harmful chemical is in your food.

Most fish farms today utilize antibiotics and other substances that may negatively affect people’s health.

Provides A Sustainable Source Of Food

Another advantage of raising fish at home is it is a sustainable way of fish farming. First, you will need less water for the pond, and because of fish tank filters, the water remains clean even after a long time.

Aside from that, all the required nutrients that the fish will provide the plants’ needs.

A fish provides a natural fertilizing method, making your garden pond similar to a natural ecosystem. It means that the plants will grow organically, unlike other fish farming ecosystems.

Less Time Required To Build

Compared to other fish farming methods, raising fish in your yard requires less time to work on. Fish can pretty much feed on the organisms in the pond, and the plants can benefit from the soil around them.

The hot tub garden pond you built is self-sufficient.


To summarize the entire article, you can turn a hot tub into a beautiful garden pond by replacing it with a hard plastic pond liner shell.

You can save money by using an old hot tub spa in your next garden pond project and raise fish in your yard.

By following the steps provided earlier, you can start raising the fish of your own choice today!