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What to do if you overfeed your fish – Everyone does it!

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We have all at some point in our Fishkeeping lives made this mistake. What to do if you overfeed your fish?

In this article, We’ll explain why it’s important not to overfeed your fish and what to do if do. Our simple step by step guide will help you avoid this common fish keeping mistake.

The most common mistake, especially for beginners is OVERFEEDING!

Don’t do it, it’s not kind to your fish and you are not doing them any favors by overfeeding them. STOP IT!

The Dangers of Overfeeding Fish

Overfeeding fish is very easy, we as humans love the interaction of feeding our fish and it’s part of the attraction of fishkeeping. Your fish will soon learn to swim to the top of the tank or come to the glass at the front of your fish tank to grab your attention.

We then automatically think they are hungry and we feed them thinking we are doing the right thing. However, what you need to remember is that fish are very small and their appetites are much bigger than their bellies!

Like small children, they love to eat too much but soon realize they can’t eat it all and leave most of the food. In a fish tank that’s really bad as the food will simply sit there and rot.

Good feeding can produce the perfect fish tank.

No signs of overfeeding in this beautiful fish tank above.

Problems that can occur from overfeeding

  • Cloudy water – This is normally the first sign that a fish tank and the fish inside are being overfed. Cure- Remove all rotting food and don’t feed your fish for a day or two. Fish are fine with this and it will not harm them and it’s not cruel. They can easily go a day or two without food. You might also consider a partial water change, whilst at the same time removing rotting food.
  • Fungus & Mold – Harmful organisms like mold and fungus will grow when there is an increased level of organic material in the water. Uneaten food will only take a day or two to become moldy. This then causes a danger especially if your fish have any damage to their fins or open wounds. Infection can quickly spread and wipe out your tank of beloved fish. Cure- Remove all signs of rotting food. Use a gravel cleaner to remove the moldy food and at the same time do a small water change to improve the quality of the water. Small particle of mold will still remain within the tank so be watchful for more fungus or signs of mold growing again.
  • Reduced Oxygen levels – Uneaten food will trigger an aerobic process that will use up oxygen within your tank and reduce the level for your fish. Cure- Remove old uneaten food and increase aeration for a few days.
  •  Increased Algae – Leftover food and dead organic matter left in the tank will increase the nitrate levels within your tank or pond and this will increase the algae levels causing your tank to become green and overgrown with green algae. Cure- If left untreated, green algae can overrun an aquarium within a short period of time. Cure – Stop overfeeding and introduce some algae eating fish and bottom feeders. Fish like these Top 10 Algae eating fish.

  • Blocked filters – As a result of overfeeding your filters may become blocked and can significantly reduce the flow rate of your tank. Without you noticing the tank can suddenly become dirty and full of ammonia which could kill your fish. Cure- Regularly check your filters and remove any signs of blockage, mold or fungus and uneaten food. Be careful how you clean your filter. If you use a sponge filter you need to follow some good practices as not to damage the good bacteria within the sponge. Read our helpful cleaning guide here.
  • Change in pH levels – Rotting and uneaten food will change the pH level within your tank. As old uneaten food starts to break down, acid levels increase and this will have an effect on the pH level of your tank. Some if are very susceptible to changes in pH levels and need constant and accurate pH levels to survive. Cure- Check pH levels after spotting uneaten or moldy food. Use a good accurate pH tester then address and adjust the pH level quickly.
  • Disease and illness- A tank with mold or fungus can lead to diseases like Fin rot, Fatty liver which is common in African cichlids. It affects the liver and can cause death to many fish. Cure- Check the appearance of your fish and look for signs on uneaten food within rocks and caves in your tank and remove. Treatments for fin rot are available. We use API MELAFIX for our Freshwater fish available from all good pet and aquarium store. We also found this product on Amazon rated very highly.
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Mold caused by overfeeding the fish in this tank.

Best ways to avoid uneaten fish food

The number one rule for feeding your fish is to give your fish a variety and well-balanced diet and feed at regular times through the day.

Resist the urge to feed on demand and never give them more food than they can eat within 5 minutes. Any food that remains in the tank after 5 minutes will fall to the bottom of the tank and hopefully will be eaten by your bottom feeders.

However, if you don’t have any bottom feeders then remove the uneaten food after an hour or so. If the food is still there after an hour the fish are not going to eat it so it needs to be removed.

Feed your fish live fish food like Brine shrimp and Bloodworms. These can be purchased at your local pet store and are a good source of protein and nutrients for your fish. They are also more likely to be all eaten by your fish as they love em. Again don’t be tempted to think you can overfeed them as they are live and won’t rot.

They will block your filter and can die and affect the water condition if your fish can’t eat them all.

Water quality

If you think the integrity and quality of your water has changed due to uneaten or moldy food then it would be good practice to do a partial water change.

It’s advisable to do a 20%-25% water change and try to remove as much of the debris as you can in this process. Using a device called a GRAVEL CLEANER will really help you safely and easily remove that unwanted food.

The video below offers helpful information on how to perform this without endangering the balance of your tank. What to do if you feed your fish and how you react is the difference between saving your beloved fish or risking losing your entire tank.

Top tips:

  • When adding new water to your fish tank, float a small plate or flat piece of plastic on top of the water, then pour the new water on top of this. It will stop a lot of disturbance to your tank and won’t damage any plants or disturb the gravel. It’s also less stressful for the fish.
  • Make sure the temperature of the water is as near to your tanks as possible.
  • Use a good water Decholrinater like Fluval water conditioner to stabilize the new water and make if tank safe before adding. 
  • Never do more than a 25% water change at any time. Small and often is better than a big water change.
  • For larger tanks use a pump rather than a manual siphon to remove the old water, it saves a ton of time.
  • Add a siphon stop tap to your gravel cleaner it makes it much easier to control the flow of the water coming out of your tank.
  • Remove the old water slowly, this won’t stress your fish out too much. The number one killer of fish is stress!
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Algae can take over if you overfeed your fish. Like this example above!

Automatic feeders for vacation times

What’s the best way to ensure your friend or neighbor don’t overfeed your fish whilst you’re away on vacation? You can’t, so invest in an automatic fish feeder.

Automatic feeders are the best method as you can control the amount of food your fish are fed each day whilst you’re away. Technology has come a long way over the past few years and automatic feeders are no longer a hit or miss guessing game.

They are a precise and accurate way to feed your fish. Now we’re not saying you should use them all the time, where is the fun in that?

But we do think it’s a safer option than asking a non-aquarist friend or neighbor to feed your fish whilst you’re away.

If they overfeed your fish which as we have just learned is easy to do, they simply won’t know they have done that and certainly won’t know how to correct it. The temptation for them to think they can give them a little bit extra so they don’t have to come in later that day will be huge.

They may also look at your fish and think ‘ they look skinny ‘ and give them a little extra.

We like and use the – Eheim Battery Operated Auto Fish Feeder available on Amazon. We found it very accurate and easy to use. 

A safe and easy option for feeding your fish whilst away on vacation or business.

Final Thoughts

Knowing how harmful overfeeding is to fish is the best way to avoid overfeeding them. We want to try and avoid you finding out the hard way by losing your beloved fish or having to battle fin rot and other diseases in your tank.

Developing good practices and procedure when feeding your fish will ensure you have a healthy tank and healthy fish.

Remember fish have eyes bigger than their bellies.!

The second point we hope that’s you’ve taken away from this article is to offer a balanced diet. Fish are not different in their feeding habits than us. Would you like to eat lettuce only for the rest of your life? No! Then make sure you offer a well-balanced diet for your fish. Live food, flakes, pellets and even frozen food are now available so you have a mountain of options available to you.

Keeping a beautiful and healthy aquarium is simple and most issues are caused by doing something excessive. Feeding, overstocking, over cleaning, overheating and making silly mistakes.

Keep it simple and if unsure ask a professional at your local store, they will always offer good advice or comment on any of our blogs and we’ll be happy to reply and help you.

We also have a Facebook group that are always willing to help Fishkeeping Forever Facebook.

Good luck and enjoy your fish!

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