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Bitterling Fish Overview, Care, Diet, Mates & More

Bitterlings are one of the cutest fish that can glow up your tank with their utter brightness.

These small carp-like fish of the Cyprinidae family are noted for their unusual breeding manner, making them more exceptional.

These shiny silver little creatures with peaceful temperaments are among the best choices to be added to your family. So, if you want to know more, keep reading this article.

Bitterling is a native of the Rhone river basin in France and the Neya river in Russia. They grow up to 4-inches and live till 5-6 years. These fish are very peaceful and best kept in a group of 6 to 8 other small fish. They are completely easy to take care of in a 30-gallon tank.

Species Overview

Level of CareEasy
AppearanceGray-green back with silvery-white sides and rose-colored fins
Life Expectancy5 years
Size1.2-4 inches
Tank Size30-gallon
Tank EnvironmentNeutral or slightly alkaline water condition that is neither too hot nor too cold
Tank MatesPeaceful

They, also called Rhodeus Sericeus, are known to be the only species of its genus “Rhodeus.” They are known as native to stony, clear rivers of Southern and Central Europe.

This fish spawns in still or slow-running clear water, sometimes with a muddy bottom. But their shiny body color with a touch of rosy red hue on the sides and an orange belly makes it an aesthetic choice for your tank.

Generally, This fish can refer to any species of Rhodeus and Acheilognathus. However, they are 23 types of bitterlings; European bitterling, Giant Chinese bitterling, Taiwan bitterling, etc. And each of them has more or less the same significance, along with being easy-going.


Do you know a recent study has shown that both males and females of this fish species have their color definition? Well, they have their respective reason behind it.

Males show red, blue, and green colors in specific regions of their skin. In contrast, the females show a subdued silver body color.

And the sole reason behind this is the different chromatophore densities and effects of androgens. Thus, the identification of male and female is too easy.


Bitterlings are generally smaller in size and don’t grow much big. They usually grow up to 1.2-1.6 inches, but some can even extend to 4-inches.


Fish are generally short-lived fish. They live up to 5-6 years subject to proper diet and adequate care. But unfortunately, many don’t even survive the year of their first reproduction.

Behavior & Temperament

They are generally very peaceful shoaling ones and do not bother their mates at all. As they are pretty easy-going fish, they can be kept in a group of 6 or even more.

Their populations mix quite well with fish of similar temperament and size, which enjoy identical fast-flowing water conditions. Also, they neither nip the fins of their buddies nor show aggression. Thus, such nature of these fish makes them perfect tank mates.

Ideal Tank Conditions

Albeit bitterling populations don’t need half of your time to be taken care of, to assure they live a long and safe life, you must take special care of your little buddy. And to begin with the mission, the first thing you must consider is a proper tank setup.

Your home aquarium needs to have a balanced temperature, proper water hardness, and a neutral pH level. Also, it is better to add a top-notch automatic filtration unit to the tank of your bitterlings so that if anytime you forget to change the water, your fish will still enjoy fresh and clean water flow.

This fish is generally super active and well-known for jumping too much. Thus, it is preferable to put a secure aquarium lid to let them enjoy their territory inside the tank and not outside.

Since these fish are schooling fish and can be kept together with an entire group of fish, make sure your aquarium contains enough space for them to hover around freely without bothering other specimens.

Tank Setup

Now, to make sure your fish grow up in a healthy and good aquatic environment, it is crucial to set up a fully facilitated tank. And this is the reason why you must take special measures to make the tank suitable for your bitterlings.

So, here are some factors that you can consider to make a better living for your shiny little mates.

  • Bitterlings might not seem to be demanding, but they are very active fish. And that is why a small aquarium is not something that would go well with them. They require enough space to wander about, which is the very reason why they need a tank of a minimum of 25-30 gallons.
  • These European fish are very specific with water temperature and don’t prefer it to be too extreme cold or hot. Thus, the temperature of the tank water must be kept within 64–75 ℉.
  • Rhodeus generally don’t prefer the water to be too hard and untidy as they are way too sensitive. Hence, make sure to balance the general hardness level of the water between 4-10 dKH.
  • It doesn’t end here, as the next thing you should keep in mind is the pH level of the water. It is preferable to maintain a pH range between 7-7.5, as it will keep them healthy and safe.
  • Bitterlings prefer dwelling on a muddy or sandy substrate. So, you can add some soil to create a muddy base in your aquarium with some plants, rocks, and stones in it for their playful activities.
  • Generally, people prefer to light up their tanks to have a better view of their fish. But in the case of bitterlings, it is better to avoid equipping any lighting fixture, as they seem to keep up the shine and brightness inside the aquarium with their glittery silver body.

Bitterling Tank Mates

So, are you wondering which fish to add along with your bitterlings? Due to their peaceful and non-aggressive temperament, these fish can be kept with any other fish. Nevertheless, they are best kept with fish that are of the same size and don’t have sharp or long fins.

As these fish are way too peaceful, if they are kept with long-finned fish, they neither can defend themselves nor attack to avoid being tortured. Generally, it’s better to keep them with torpedo-shaped nemacheilidae loaches, which include the following.

  • Schistura
  • Mesonoemacheilus
  • Nemacheilus

Apart from them, bitterlings also go well with a few sub-tropical botiidae and weather loaches. Some of them are as follows.

  • Sinibotia Pulchra
  • Ambastaia Nigrolineata
  • Misgurnus Anguillicaudatus
Bitterling looking at camera

Food & Diet

When it comes to feeding your little new silver member of your family, it is not at all a headache. Being both schooling and easy-going fish, bitterlings don’t have too many demands for feeding.

Since they are omnivorous by nature, in the wild, they primarily feed on plants, and to a very lesser extent, upon crustaceans, insects, and worms.

So, when in captivity, they can easily feed on both plants and invertebrates. Also, you can offer your tiny friends flakes or small frozen foods such as brine shrimp, mosquito larvae, daphnia, and micro granules.

Besides keeping your bitterlings on an animal diet, you can also set a plant or vegetable diet for them. You can feed them some fresh veggies.

However, it will be best to keep alternating their diet and provide them with vegetable and animal-based nutrition to maintain their good health.

So, are you now wondering how often you should feed these fish? Since they are too tiny, it’s better to provide them in small portions instead of a large feeding.


Caring is an easy job for these fish. All these fish want is ample space to roam, jump, and fool around.

While taking adequate care of these Rhodeus species, you need to change the tank water routine-wise every week. It’s essential to provide them with good and clean quality water for their healthy growth.

Do not forget to keep checking the water parameters like hardness, temperature, and other factors to ensure that you facilitate your bitterlings with the best care. Also, you should vacuum the substrate once a month to keep it clean enough for your fish.

Breeding Guidelines

Bitterling male and female looking at a mussel for spawning

So, are you super excited to bring baby bitterlings into your aquarium? Well, then there are certain things that you must know about their breeding process. These are highly known for their unusual and fascinating spawning mechanism.

In the wild, this bitterling Rhodeus species is a mussel-spawner. So, when you are breeding this species in your home aquarium, to mimic their natural habitat site, the tank must contain at least one unionid bivalve freshwater clam.

The females lay their eggs in the gills of a fresh, clear water mussel. The male fish, which display brilliant colors during the breeding season, quickly follow the females and sprays their sperm in the gill cavity of bivalve freshwater mussels. And this further results in the fertilization of the eggs.

The eggs generally stay inside the mussel’s gill cavity for around 4 weeks. After hatching, the baby bitterlings remain within the clam itself for about 1-month. And after they grow a bit large to fend for themselves, they leave the freshwater mussels as active larvae.

Interesting Facts

So, do you want to know some fun facts about bitterling Rhodeus? Well, then, here are some genuinely interesting facts about them. Have a look.

  • Both the sexes of this species reach sexual maturity in almost 1-year that too at a length of 30 to 35 mm.
  • These fish were once used for testing human pregnancy. Female bitterlings were injected into the urine of those women who were supposed to be tested. The hormones in the urine caused the fish’s ovipositors to protrude if the woman was pregnant.
  • The male specimens are too colorful and thrive well with North American sunfish and Weather loach.
  • They neither prefer constant running water nor mix well with fish that prefer to love such water conditions.

Where to Buy?

Bitterling fish are easy to spot in many aquarist stores worldwide, as this particular species is not rare at all.

Generally, doing trade of these fish is legal in many places and doesn’t require a license to purchase them. But there are some places where a license becomes necessary for buying these fish.

Also, in many places, you will see, instead of using the common name, bitterling, the traders use their species name, Rhodeus. So, don’t get confused; they correspond to the same fish!

However, if you don’t find these fish in usual pet stores, you can easily get them from any hobbyist. Apart from that, purchasing online is another widely available option.

Final Thoughts

These fish are generally known as cold water fish; thus, they can be easily kept in tanks with proper water parameters.

Also, offer them an appropriate tank set up to take good care of them. If you are done with that job, 80% of your work is done to provide them with an aquatic environment similar to their natural habitat, increasing their longevity.

Also, bitterlings are well-known to be wonderful aquarium fish, owing to their peaceful, hardy, and energetic nature. Thus, whether you are a beginner or an expert aquarist, you can easily keep these fish in your home aquarium, enhancing its beauty.