Freshwater Flounder Care Guide: Appearance, Diet, Breeding & All | 2022

By: Martin McAdam
Updated: June 11, 2022

If you want to catch a Freshwater Flounder, you'll need to know a thing or two about this bottom-dwelling fish. Freshwater Flounders are members of the flatfish family, including sole, halibut, and turbot. They are found in salt water and fresh water environments around the world.

They are pretty elusive, as they live on the sea/river bottom and can blend in well with their surroundings. However, catching freshwater flounder is possible if you know what to look for.

Let's take a closer look at some of the things you'll need to know about Freshwater Flounders to catch them successfully.

Species Summary

Scientific name:Trinectes maculatus
Common names:American freshwater Flounder, common Flounder
Family:Achiridae
Range:North America (the United States and Canada)
Size:Up to 6 inches in length
Lifespan:3 to 5 years
Habitat:Freshwater rivers and lakes
Behavior:Solitary, bottom-dwelling fish
Tank size:5–10 gallons
Water temperature:72°–86°F (24°C – 28°C).
ph Range:8.0–8.2
Water hardness:12–14 dGH or higher
Water Type:Freshwater
Activity Level:Low
Feeding habits:Bottom feeder, feed on smaller fish and insects
Compatibility:Generally peaceful, though large freshwater Flounder may be aggressive towards smaller fish
Tankmates:Other freshwater fish
Care Level:Easy
Breeding:Difficult
Diet:Carnivorous, feed on smaller fish and insects

The Freshwater Flounder that we commonly see and enjoy in our freshwater lakes and rivers is a unique fish belonging to the family Achiridae of flatfish. They have been found from Cape Cod down to Argentina, but their greatest concentration resides in North America along 10° C and warmer waters.

Freshwater Flounder Species Summary

They cost between $10 and $12 per pound and are found in fish markets around the country.

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Freshwater Flounder Appearance

They have a flat oval-shaped body with both eyes on one side, which allows them to camouflage themselves on the river bed or lake floor. Their mouths and gills are at the top of their head, so they can feed on smaller fish and insects that fall from above.

Freshwater Flounder Appearance

This fish does not have scales but has smooth skin covered in mucus. This slimy barrier protects them from parasites and helps them to stay hidden from predators.

The Freshwater Flounder can easily camouflage to fit in with the environment, and it is often difficult to distinguish this fish from other river bottom debris.

Their coloration can vary depending on their surroundings, but they are typically brown or green with dark spots. The underside of their body is usually white or pale yellow.

They are found in freshwater rivers, lakes, and estuaries throughout the United States, Canada, and South America.

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Freshwater Flounder Size & Growth Rate

Freshwater Flounders can grow up to 6 inches in length, though most are smaller. They generally grow pretty slowly, with females growing faster than males.

Freshwater Flounder Size & Growth Rate

However, their slow growth rate means they are much more susceptible to environmental changes and pollutants, so it is essential to be careful when fishing for Freshwater Flounder.

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Freshwater Flounder Lifespan

Freshwater Flounders can live for 3 to 5 years and are generally long-lived fish.

However, the average lifespan is often shorter due to the many predators that target them.

Freshwater Flounder Lifespan

Read Also: Pipefish

Freshwater Flounder Breeding

Freshwater Flounders are not known to breed in captivity. If you are interested in breeding them, you will need to obtain a group of juvenile Flounder and raise them together.

It is important to provide the Flounder with a large tank with plenty of hiding places, as they tend to be shy fish. You should also maintain a regular feeding schedule and provide them with a varied diet.

If you successfully breed freshwater Flounder, the female will lay her eggs on the substrate, where the male will fertilize them. The eggs will hatch after about two weeks, and the fry will be free-swimming after another week.

Freshwater Flounder Behavior & Temperament

Freshwater Flounder tend tоo be peaceful fish, getting аlоng well with mоѕt оthеr соmmunаl fish in a freshwater aquarium. They are not known to be aggressive or territorial towards other fish. In the wild, they are bottom-dwellers and prefer to stay close to the substrate.

Freshwater Flounder Behavior & Temperament

They may sometimes be shy in an aquarium setting, preferring to stay near the bottom of the tank. When they occasionally venture up towards the top of the tank, Flounders tend to do so in short bursts before quickly returning to the bottom.

To get a picky Freshwater Flounder to eat, try offering them live or frozen foods, as they are more likely to be interested in these than dried flakes or pellets. They are not known to be particularly active fish, but they can sometimes be playful and curious.

However, with proper care and a healthy environment, most freshwater flounders will eventually feel at home in their new surroundings and become more active and social over time.

Freshwater Flounder Care

Their care is easy, as long as their tank mates are not too small. They are peaceful fish that generally get along well with other freshwater fish.

However, they can be aggressive towards smaller fish, so it is important to choose tankmates carefully.

It is also essential to provide them with a tank with plenty of hiding places to feel safe.

Here are some other things to keep in mind when caring for Freshwater Flounder:

Tank Size

Because of their slow growth rate, they can thrive in smaller tanks. A Freshwater Flounder kept alone will be happy in a 5-10 gallon tank. And a pair can be satisfied in a 20-gallon tank.

When setting up your tank, use an aquarium background and substrate to help camouflage them.

Water Parameters

Water quality is essential for all fish but significant for freshwater flounders. They are susceptible to changes in water quality and can easily succumb to disease if their tank is not maintained correctly.

The ideal water temperature for Freshwater Flounder is 72°–86°F (24°C – 28°C). The pH should be between 6.5–8.0, and the water hardness should be between 4–10 dGH.

Maintaining a high level of dissolved oxygen in the water is also essential, as they are known to be oxygen-sensitive fish.

It is recommended to use a filter and to perform regular water changes.

Filtration

If you are using a filter, it should be able to handle at least 20 times the volume of your tank. This will help to keep the water clean and free of debris while also ensuring that the fish have enough oxygen in their tank.

Water aeration is another good option for Freshwater Flounder tanks. If possible, try to set up an air pump and add airstones to your tank. This will help increase the oxygen levels in the water and make it more difficult for disease-causing bacteria to thrive.

Some recommended filtration options include:

  • Sponge filters: These are great for freshwater flounder tanks because they provide mechanical and biological filtration.
  • Canister filters: Canister filters are another good option for freshwater flounder tanks. They provide mechanical and biological filtration and can be hidden behind aquarium décor to help keep the tank looking clean.
  • Undergravel filters: Undergravel filters are a good option for freshwater flounder tanks because they provide mechanical and biological filtration. They are also easy to install and maintain.
  • Foam filters: Foam filters are a good option for freshwater flounder tanks because they provide mechanical and biological filtration. They are also easy to clean and maintain.

Heating

Using a heater in your Freshwater Flounder tank is essential if you live in an area with a cold climate. The ideal water temperature is between 72°– 86°F (24°C – 28°C).

You can use either an aquarium heater or a submersible aquarium heater. If you are unsure how to install the heater, read the instructions carefully before use.

Some recommended heating options include:

  • Submersible aquarium heaters: These are a popular and common option for tanks. They can be installed quickly and come in various sizes to suit your tank.
  • Undertank heaters: Undertank heaters are another good option if you live in an area with cold weather. They are well-hidden in the gravel, so they don't affect the overall appearance of your tank.

Lighting

The ideal lighting for Freshwater Flounder tanks is bright and indirect, which can be achieved using a combination of overhead lights and floor lights.

Some recommended lighting options include:

  • LED aquarium lights: LED aquarium lights are a good option for tanks because they are energy-efficient and long-lasting. They also produce very little heat, so they won't affect the water temperature in your tank.
  • Fluorescent aquarium lights: Fluorescent aquarium lights are another excellent option for tanks. They are relatively inexpensive and easy to find.
  • Metal halide aquarium lights: Metal halide aquarium lights are a good option for freshwater flounder tanks because they provide very bright light. However, they can produce a lot of heat, so be sure to use them with an aquarium fan or chiller to keep the water temperature in your tank stable.

Plants

Freshwater flounder tanks should be planted with a variety of live plants. It will help create a natural environment for the fish and provide them with hiding places.

Some recommended plant options include:

  • Java fern: Java fern is a good option for tanks because it is easy to care for and does not require a lot of light.
  • Bolbitis: Bolbitis is a good option for tanks because it proliferates and helps to reduce algae growth.
  • Java moss: Java moss is a good option for tanks because it provides hiding places for the fish and helps filter the water in the tank.
  • Anubias: Anubias are another excellent option for tanks because they are easy to care for and do not require much light.

If you are unsure how to plant your freshwater flounder tank, read the instructions carefully before use.

CO₂ Systems

In addition, to live plants, freshwater flounder tanks may also benefit from using a CO₂ system. These systems add extra nutrients and oxygen to the water, helping your fish thrive.

There are many different options for CO₂ systems, including:

  • Compressed gas tanks: Compressed gas tanks are a popular and common choice for CO₂ systems in freshwater flounder tanks. They are easy to install and do not require electricity, so they are ideal for aquariums that don't have access to power.
  • Powerhead diffusers: Powerhead diffusers are a good option if you want to add a lot of CO₂ to your tank. They are easy to install and can be used with various aquariums.
  • DIY CO₂ systems: DIY CO₂ systems are a good option if you want to save money on your CO₂ system. You can find many tutorials online on building your DIY CO₂ system for your freshwater flounder tank.
  • Bottled carbon dioxide gas: Bottled carbon dioxide gas is a good option if you want to add a small amount of CO₂ to your tank. It is easy to use and does not require any special equipment.

Water Conditioners

In addition to plants and CO₂ systems, freshwater flounder tanks may also benefit from water conditioners. This help improves your tank's water quality by removing harmful impurities, such as chlorine and heavy metals.

There are many different types of water conditioners available, including:

  • pH buffers: pH buffers are a good option if you want to stabilize the pH levels in your tank. They are easy to use and can be found at most pet stores.
  • Nitrate reducers: Nitrate reducers are an excellent option if you want to reduce the levels of nitrates in your tank. They are available in chemical and biological forms, so be sure to choose the one that is right for your fish.
  • Ammonia removers: Ammonia removers are a good option if you want to remove harmful ammonia from your tank. They are available in chemical and biological forms, so be sure to choose the one that is right for your fish.

Water conditioners are an essential part of any freshwater flounder tank and should be used regularly to keep your fish healthy and happy.

Substrate

The substrate in your freshwater flounder tank is also important. This is the material that covers the bottom of the tank and helps to keep the water clean.

There are many different types of substrates available, including:

  • Gravel: Gravel is a common substrate for Freshwater Flounder tanks because it helps to keep the water clean and allows plants to easily take root.
  • Sand: Sand is another common substrate for freshwater flounder tanks because it does not get disturbed as easily by the fish, making it perfect for smaller species that prefer to bury themselves.
  • Plastic plants: Plastic plants are a good option for freshwater flounder tanks because they are easy to care for and do not require a lot of light.
  • Clay: Clay is another common substrate for freshwater flounder tanks because it helps to keep the water clean and can be used in combination with live plants.

If you are unsure which substrate is suitable for your tank, consult an aquarium expert or read the instructions carefully before use.

Decorations

In addition to the substrate, decorations are essential to your Freshwater Flounder tank. These include anything from rocks and driftwood to plastic plants and live plants.

Decorations serve many purposes in an aquarium, including:

  • providing hiding places for fish
  • absorbing excess nutrients from the water
  • and adding to the overall aesthetic of the tank

When choosing decorations for your freshwater flounder tank, select items that are safe for use in an aquarium and will not disturb the ecosystem's delicate balance.

Other Tank Accessories

In addition to a heater and lighting, you may want to consider other pieces of equipment for your freshwater flounder tank.

These can include:

Air pump: An air pump helps to circulate the water in your tank, providing your fish with more oxygen and helping to keep the water clean.

Water test kit: A water test kit is an important tool that you can use to test the levels of ammonia, nitrites, and nitrates in your tank. This will help you keep the water clean and safe for your fish.

Aquarium salt: Aquarium salt is a good addition to any Freshwater Flounder tank, as it helps to reduce stress and promote healing.

Freshwater Flounders are a popular choice for many aquarium enthusiasts because they are relatively easy to care for and make a great addition to any freshwater tank. With a little bit of research and planning, you can create the perfect environment for your fish.

Water Changes

Water changes are an important part of freshwater flounder care. Regular water changes help keep the water clean and remove any unwanted toxins or chemicals that may harm your fish.

When performing a water change, be sure to:

  • use a siphon to remove the dirty water from your tank,
  • replace the dirty water with fresh, clean water,
  • and add a water conditioner to the new water to remove harmful chemicals.

Water changes should be performed every two weeks to keep the water clean and your fish healthy.

Cleaning The Tank

In addition to regular water changes, it is also important to clean the gravel and decorations in your tank regularly. This helps remove any toxins build-up and keeps the water quality high.

To clean the gravel and decorations in your freshwater flounder tank:

  • remove all of the gravel and decorations from the tank,
  • rinse the gravel and decorations in clean water,
  • and return the gravel and decorations to the tank.

Cleaning the tank should be done every month or as needed.

Cleaning The Filter

The filter is an important piece of equipment in your freshwater flounder tank, as it helps to keep the water clean and free of toxins.

To clean the filter:

  • remove the filter from the tank,
  • rinse the filter media in clean water,
  • and return the filter to the tank.

Cleaning the filter should be done every month or as needed.

With regular water changes and cleaning, you can help to keep your freshwater flounder tank in top condition and ensure that your fish live a long and healthy life.

Testing The Water

In addition to regular water changes and tank cleaning, it is also important to regularly test the water in your freshwater flounder tank. This will help you identify any potential problems early on, allowing you to take action before they harm your fish.

Purchase an aquarium-specific water test kit, follow the instructions included with the test kit to determine the levels of ammonia, nitrites, and nitrates in your tank, and take any necessary steps to address any issues that are identified.

Testing the water should be done at least once a month to help ensure optimal water quality for your fish.

Common Possible Diseases

One of the biggest concerns for Freshwater Flounder owners is disease risk. While there are several different diseases that these fish may be susceptible to, some of the most common include.

  • Fin rot: This disease is caused by poor water quality and is characterized by fraying, rotting, or falling away of the fins. You will need to clean your tank thoroughly and administer regular water changes until the disease has cleared up to treat fin rot.
  • Ichthyophthiriasis (ich): This disease is caused by a parasitic infection and is characterized by white spots on the fish's body. To treat ichthyophthiriasis, you will need to raise the temperature of your tank and administer medication specifically designed for this disease.
  • Columnaris: This disease is caused by poor water quality and is characterized by lesions on the fish's body. To treat columnaris, you must clean your tank thoroughly and administer regular water changes until the disease has cleared up.
  • Fungal infections: These infections are caused by poor water quality and are characterized by growths on the skin or fins of the fish. To treat a fungal infection, you must clean your tank thoroughly and administer medication specifically designed for this disease.
  • Bacterial infections: These infections are caused by poor water quality and are characterized by lesions on the fish's body. To treat a bacterial infection, you must clean your tank thoroughly and administer medication specifically designed for this disease.

If you notice any illness or disease in your fish, it is important to consult a veterinarian immediately. With proper treatment, it is often possible to help your fish recover and return to good health.

Overall, freshwater flounders make an excellent choice for hobbyists looking for a fun and low-maintenance aquarium fish. To care for these fish properly and keep them happy and healthy, be sure to perform regular water changes, clean the tank and filter often, and test the water regularly.

Preventing Diseases

The best way to prevent diseases in your Freshwater Flounder is to provide them with a clean and well-maintained tank. Be sure to perform regular water changes, clean the tank and filter often, and test the water regularly to help ensure optimal water quality for your fish. Additionally, it is important to quarantine new fish before introducing them to your established tank, as this can help prevent the spread of diseases.

In addition to providing proper care for your Freshwater flounder tank, you can also do many other things to minimize the risk of illness or disease in your fish. For example, you can add aquarium-safe bacteria supplements to help promote healthy and sustainable bacterial growth in the tank or aquarium-safe cleaning chemicals to help minimize build-ups of harmful substances.

Overall, providing proper care and taking a few simple preventative measures makes it possible to keep your Freshwater Flounder happy and healthy for many years to come!

Treatment And Medications Of Diseases

Some very effective medications and treatments are available to help manage and treat diseases in freshwater Flounder.

  • Fin rot can be treated with several different antibiotics, such as amoxicillin or chloramphenicol.
  • Ichthyophthiriasis can be treated with a number of different medications, such as metronidazole or erythromycin.
  • Columnaris can be treated with a variety of different medications, including furazolidone or potassium permanganate.
  • Fungal infections are often treated using antifungal medications, such as acriflavine or malachite green.
  • Bacterial infections are typically treated using antibiotics, such as tetracycline or amoxicillin.

Suppose you notice any signs of illness or disease in your freshwater Flounder. In that case, it is important to consult a veterinarian right away so that proper treatment can be administered as soon as possible. With proper treatment and care, it is often possible to help your fish recover and return to good health.

Food & Diet

To keep your Freshwater Flounder healthy and happy, it is important to provide them with a balanced diet consisting of various foods.

Good food sources for Freshwater Flounder include high-quality fish flakes or pellets, small live or frozen fish, brine shrimp, bloodworms, and other worms.

It is also good to supplement your Freshwater Flounder's diet with occasional treats, such as freeze-dried shrimp or krill. They also like to graze on algae, so you may consider adding some live plants to your tank for them to nibble on.

To ensure that your fish are getting the nutrients they need, it is essential to feed them various foods.

Diet Foods To Avoid

Many foods should be avoided when feeding a freshwater flounder.

For example, avoiding overfeeding your fish is best instead of sticking to a regular feeding schedule. In addition, you should avoid high-fat and spicy foods, such as raw shrimp or other crustaceans. You should also avoid using table scraps as fish food, as this can often contain harmful chemicals or other substances that can harm your fish's health.

Feeding Schedule

Establishing a regular feeding schedule is important to keep your Freshwater Flounder healthy and happy. Generally speaking, you should aim to feed your fish several times daily, giving them small portions at a time. This can help minimize the risk of overfeeding or other issues with food waste in the tank. Some good feeding times to consider are early in the morning, at midday, and late in the evening.

Tank Mates

Freshwater Flounder are generally peaceful fish that do well with other соmmunаl fish in a freshwater aquarium. They are not known to be aggressive or territorial towards other fish. But they are so shy that they often don't do well with very active tank mates.

This fish doesn't enjoy living in crowded environments, so you should be sure to provide them with plenty of space in their tank.

It is important to avoid keeping Freshwater Flounder with aggressive or territorial fish, as this can lead to stress and conflict in the tank. In addition, you should avoid keeping them with very large fish, as these may see the Flounder as potential prey.

Advantages Of Having Freshwater Flounder In Your Tank

The first advantage of having a Freshwater Flounder in your tank is that they are relatively low-maintenance fish. They are not known to be particularly active, so they do not require a lot of space. In addition, they are not known to be aggressive or territorial, so that they can get along well with other соmmunаl fish in your tank.

Another advantage is that they are relatively hardy fish, making them a good choice for beginners or those with little experience with freshwater aquariums. They are also quite playful and curious at times, so keeping them can also be entertaining.

Disadvantages Of Having Freshwater Flounder In Your Tank

The main disadvantage of keeping Freshwater Flounders is that they can be pretty shy in an aquarium setting. This means that you may need to spend a lot of time coaxing them from the substrate or getting them to eat.

Another potential issue is that they are not very active fish, so they may not do well with busy tank mates. In addition, they are not known to be particularly social fish, so they may not interact much with other fish in your tank.

Wrapping Up

As long as you are prepared for the potential challenges of keeping a freshwater flounder in your tank, they can make exciting and entertaining pets. However, it is important to be aware of their specific needs and requirements so that you can provide them with the right environment and care to help them thrive. If you consider all of these things, you will have a great experience keeping freshwater Flounder in your tank!

I hope this article has been helpful in teaching you all about freshwater Flounder. Thanks for reading!

Disclaimer

AquaMarinePower.com does not intend to provide veterinary advice. We go to great lengths to help users better understand their aquatic friends. However, the content on this blog is not a substitute for veterinary guidance. For more information, please read our disclaimer.

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