Using Poultry Manure in Fish Ponds

Green water is the goal, and too much of it is the trouble

Green water is food, until it turns into a smell. A pond dressed with dry manure will usually turn green within a week or two in warm weather, if the water is still. That green is plankton, a soup of tiny algae and the small animals that eat them, and it is what tilapia graze on. Keep the bloom in balance and the fish do well. Let it run away and the same pond can crash overnight.

Oxygen, more than disease, is what kills fish in an over-manured pond. The bloom makes oxygen while the sun is up and uses it through the night. The lowest level comes in the hour before dawn, and a dense bloom can drop the dissolved oxygen to a dangerous level just when the fish are most stretched.

This is a pond article, so it stays on the pond. The wider picture of crops, fish and litter together is covered in our guide to integrating poultry with crops and fish, which is worth reading alongside this one.

What manure adds to a pond, and what it cannot do

Dried poultry manure carries nitrogen and phosphorus, the nutrients that feed the plankton, along with organic matter that bacteria break down. Many Ghanaian ponds are short of both, so a measured dressing does what fertiliser does on a maize field. It starts the chain that ends with the fish.

It cannot make up the full diet of a fish that is growing fast. Plankton is a useful supplement, and a well-managed pond can grow small fish on it for a while, but a fish that is stocked heavily or taken to a set size needs a feed with the protein and energy the water cannot supply. Keep two accounts in your head: the manure is the pond's fertiliser, and the fish feed is the fish's food. Do not expect one to pay for the other.

Halaal Farms is a day-old chick hatchery and importer in Kasoa, and we do not sell fish or fingerlings. Our interest in pond manure is the poultry side of the farm: the litter and droppings that many poultry keepers are looking for a sensible use for. If you are still deciding on the flock, our layer chicks and broiler chicks pages describe the two usual starts, and each one produces a different kind of manure.

Dry the manure before it touches the water

Fresh poultry droppings are wet, hot and loaded with ammonia and bacteria. Carry them from the house straight to the pond and you add a load the water cannot absorb. Ammonia becomes more toxic as the pH rises, and a pond at dawn with high pH and fresh manure is the one most likely to lose fish.

Dry the manure on a clean, raised surface under cover, turning it until it is crumbly and no longer sticky. Spread it thinly so the air reaches it. Let it rest for a week or two before it goes near the water, and keep the heap covered when the rains come. Store it off the ground in a dry shed with a roof. Wet manure lying on a pond bank is a slow leak into the pond every time it rains. Our composting guide covers the other route for wet litter, which is a heap that heats and rests before it goes anywhere near water.

Sieve the dried manure before use. Feathers, lumps of wet litter and bits of plastic do no good in a pond and can foul the outlet or the pump.

Reading the water with a Secchi disc and your own eyes

A Secchi disc is a white or black-and-white disc on a marked rope. Lower it into the water until it disappears, note the depth, then lower it a little further and raise it until you can see it again. Average those two depths and you have your transparency reading. Many tilapia guides aim for a transparency of roughly 25 to 40 centimetres. Clearer than that and the pond is probably short of plankton. Darker than that and oxygen needs watching closely. Your fisheries officer can give you the target for your species and your pond.

Take the reading at the same time of day each time, ideally late morning when the bloom is active. Write it down with the date and the weather.

Your eyes matter as much as the disc. A pond that looks wrong to you, even when the numbers seem fine, deserves a second look before the next dose.

The basal dressing before stocking

Before you stock the fingerlings, put a basal dressing of dried manure into the empty pond, spread evenly over the bottom or across the surface in a thin layer. Fill the pond, wait for the water to turn green, and only then stock. A pond stocked into clear water has little for the fish to graze on in their first days, and the early weeks are when stress costs you most.

The dose depends on the pond's size, the soil and the species you are growing. Ask your district fisheries officer, who works under the Fisheries Commission, what they recommend for your pond. Start below the top of the range they give you. You can add more later, but once manure is in the pond you cannot take it out.

If the pond bottom is acidic, your fisheries officer may also advise liming before filling. Liming and manuring should be planned together, not done in whichever order you remember on the day. If you are stocking the poultry side at the same time, our day-old chicks page shows what we can supply for the flock.

Small top-ups, and why little and often beats one big dump

Once the pond is stocked, add small doses at regular intervals, usually weekly or every two weeks, and adjust each dose to the reading. A single heavy dump can push the bloom over the edge within a day. Small doses let the bloom rise and fall slowly, and they give you time to see the trend before it turns.

Keep a log: the date, the dose, the weather, the Secchi reading, the dawn oxygen if you can measure it, and what the fish did that morning. Write down the day you held back a dose and why. After one season, the log will tell you more about your pond than any guide can, including this one.

A small pond responds faster than a large one, so cut your doses accordingly, and check the reading two or three days after each change. Patience with manure is a skill, and most of the losses we hear about come from people who could not wait.

Dawn oxygen, and the crash you do not see coming

The lowest oxygen comes just before sunrise, on cloudy nights and after a few days of heavy manuring. Fish that come to the surface at dawn and gulp air at the edge are telling you the oxygen is low. Do not wait for them to do it every morning before you act.

For most tilapia ponds, dissolved oxygen falling below about 3 milligrams per litre at dawn is a warning. If you have a meter, measure at dawn for a few days after each dose. If you do not have one, watch the fish, and watch the edge of the pond at first light. A pump or a paddle that splashes the surface helps through the worst nights, but the first step is always to stop adding manure.

Plan the cloudy spells. A run of overcast days cuts the bloom's oxygen output while the fish still need it, so hold back doses during those weeks and check the water more often than usual.

Ammonia, colour and the smell test

A rotten-egg smell comes from the bottom of an oxygen-starved pond, where dead bloom is breaking down without air. A sharp ammonia smell comes from the water itself. Either one means the pond has gone past its comfortable point. Do not stir the pond to hide the smell. Stop the manure, let the bloom settle and measure the oxygen.

Watch the colour as well. A pond that turns brown after heavy rain may have washed soil into it, and that brown water needs less manure, not more. A pond that turns milky after a heavy dose may be a bacterial bloom, which also needs less manure and sometimes more aeration. In both cases the fix starts with holding back the dose.

Where the manure comes from, and what to keep out of it

Manure from layers, broilers and cockerels behaves similarly, but the bedding changes the result. Litter made from wood shavings or rice husks is drier and easier to handle than droppings mixed with wet, spilled feed. Keep wet bedding out of the heap, keep dead birds out completely, and sieve out feathers and anything plastic before the manure is dried.

Ask your vet about withdrawal periods before you use manure from birds that have been treated with medicines. Residues in manure can affect the water and the fish, and you should not guess how long to wait. Keep manure from treated flocks separate until your vet has told you it is safe to use, and label the heap with the date and the flock it came from.

Our biosecurity guide sets out how to keep the manure store and the flock apart, which is the same discipline that keeps the pond clean. If you plan to sell the surplus as fertiliser instead, our guide to using and selling poultry manure covers drying, bagging and pricing.

A worked example for a 300 square metre pond

Imagine a 300 square metre pond beside a small layer flock, with the manure dried under a roof at the end of the house. The table is a plan, not a formula. It shows the reading to aim for at each stage. Your fisheries officer should give you the dose for your own pond, and the numbers in the table are not doses.

The sequence matters more than any one number. A pond that goes green on schedule, holds its oxygen through the dawn checks and gets its manure reduced as the fish grow is doing what it should. A pond that needs a dose every week to stay green is telling you it has too many fish, too little water exchange or a feeding problem somewhere else.

Mistakes that turn a fish pond into a stink pit

Most bad ponds were made by people who wanted fast results. The mistakes repeat from pond to pond, and you can avoid most of them with a log and a few minutes at dawn.

• Spreading fresh, wet droppings straight from the house onto the water.
• Stocking fish into clear water before the bloom has developed.
• Dosing right after a run of cloudy days, when oxygen is already short.
• Judging the pond by its colour alone, without a Secchi reading.
• Skipping dawn checks because the water looked fine the evening before.
• Ignoring fish at the edge of the pond at first light.
• Mixing manure from treated birds into the same heap as untreated manure.

Checklist before you dose the pond

1. Take a Secchi reading at the same time of day as the last one, and write it down.
2. Check the weather forecast, and hold back the dose if cloudy days are coming.
3. Look at the fish at the edge of the pond at first light, and note any gulping.
4. Check the dawn oxygen if you have a meter, or the best reading you can take.
5. Confirm the manure is dry, sieved and from a flock with no withdrawal period still running.
6. Apply the dose thinly and evenly, and note the amount and the time.
7. Recheck the Secchi reading and the dawn oxygen a few days later, and adjust the next dose.

When the pond and the flock are both running on a routine, our FAQ page answers the common questions about orders, and our delivery page covers how chicks reach every region.

Questions farmers ask