Introduction: Convert Rain Barrels to Fish Tanks for Aquaponics

About: Married to Domestic_Engineer (but I call her Meghan).
Have you been reading about aquaponics but don't know where to start?  Well, I have.  So, when my girls caught some tiny trout at a fishing derby I decided to slap together a fish habitat.

Aquaponics is basically growing plants in fish water.  So you need - fish -- water -- and plants.

This instructable only covers the fish and water.  
  1. Catch a fish
  2. Get a bucket
  3. Fill with water
  4. Get a pump
  5. Put the pump in the water
Right now we have lots of rain, so we are using the access to water the gardens.  However, this is only viable as long as it rains every few days.  Plants should be added to build a closed loop.

For  the whole system, the best book on the topic is by Sylvia Bernstein

Aquaponic Gardening: A Step-By-Step Guide to Raising Vegetables and Fish Together

  1. The fish were caught at a private club, normally fish this small would be thrown back.
  2. This includes some pictures of a dead fish  -- 'fish-topsy'

Warning -- find better instructions -- 4 weeks latter I have 2 out of 6 fish remaining.

Step 1: Go Fishing

I live in Maynard Mass.  There is a yearly fishing derby for kids at the local Rod and Gun club.

Here are some tips on fishing - 
  1. Fish eat early and late -- go as early as you can
  2. Fish eat in the shade
  3. Fish like to be in running water, so fish near an inlet or outlet
  4. Fish can hear
  5. Fish can see
  6. Fish eat flies, so fish where there are bugs on top of the water
  7. Fish eat worms
  8. Canned corn and raisins are easy to put on hooks, so is white bread in a little ball.
  9. Get short fishing poles, the kind with the button

Here is Molly catching a fish:

Step 2: Catch Fish

Here are the fish.  We brought them home in a 5 gallon bucket.

Two fish I could not remove the hooks.  One died.

Step 3: Tools

Here are the tools used to modify rain barrels for fish.

Step 4: Modify Rain Barrels

There is lots of info on rain barrels.  We have 2 on each downspout.  To access the water, I cut off a section of the lid with a saw and scrapped the edges with a deburring tool.  A lot of plastic got into the rain barrel, I scooped out as much as I could.

Step 5: Add a Pump to Circulate the Water

The water needs to be circulated and arrated.  This pump is meant to drain a pool cover.

Step 6: Put the Pump in the Water

The goal is to circulate the water between two rain barrels, to give the fish 100 gallons of water.  Fish can breath under water (of course) but they still need air to be in the water.  Small fish tanks often have an air pump, but air can also be added by making a little water fall.  In this case the water cascades from one barrel to the next.

This shows the basic setup, water is pumped from the lower barrel into the upper barrel.  I've removed an overflow spout to allow the water to freely flow into the lower barrell.

Step 7: Adjust the Flow Rate

If the pump is faster than the drain, the upper barrell will overflow and you will run out of water.  If water spalshed out of the bucket, you will run out of water.

To solve these problems, I added a clamp to slow the flow from the pump.  I do not know what this clamp is actually for.   I also added a pipe to keep water from dribbling down the side of the barrel.  Wrapping the pipe with electrical tape, them jamming it in a hole, makes a workable seal.

Step 8: Add Fish

Let that run for a while to make sure there are no leaks.  Then dump in the fish.


Step 9: Feed the Fish

Feed the fish some worms.

After a few hours, the open barrel started attracting insects which the fish can eat.

Step 10: Maintain the System

At this time, we have been running the system for over 2 weeks.  The 5 fish are still alive.  When it rains we drain off water into the garden.  The pump has needed to be wiped clean a few times.  We will have to add a coarse pre-filter, like a bucket with holes.

I have to add a section of plants to filter the water.

The next step is a fish autopsy.  It shows why one fish with a stuck hook died. 

Step 11: Fish Autopsy

I have noticed that sometimes when you catch a fish it will suddenly die.  Other times it might still be moving after you've chopped the head off.  I carefully cleaned (cut open) the fish that died.  It turns out that the hook was directly next to the heart.

Step 12: Add Plants

This project is on going.  I am adding a bucket of plants in gravel which the water will cycle through.

Gardening Challenge

Participated in the
Gardening Challenge