The Most Difficult Fish to Keep, Ranked
Voting rules: Choose the fish you think is the most difficult!
Updated on Apr 16, 2024 06:38
For many aquarium enthusiasts, the challenge of maintaining a thriving aquatic environment is part of the allure. However, some species of fish pose a higher level of difficulty in care and management, often requiring specialized conditions to survive. Determining which fish are the toughest to sustain can help both novice and experienced aquarists make informed decisions, avoiding common pitfalls associated with delicate species.
By participating in the ranking of the most difficult fish to keep, users can contribute their experiences and insights, which in turn, enriches the community’s collective knowledge. This dynamic ranking serves as a valuable resource, guiding potential fish owners in their choices and helping them set realistic expectations for the care required. Sharing personal experiences and votes ensures that the list remains current and reflective of real-world challenges.
What Is the Most Difficult Fish to Keep?
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133votesDiscus fish are notoriously difficult to keep because they have a very specific water chemistry and are prone to stress and disease. They require frequent water changes, high-quality food, and a lot of attention to maintain.The Discus (Symphysodon spp.) is a freshwater fish known for its vibrant colors and round disc-like shape. It is native to the Amazon River basin in South America. The popular species kept in aquariums include Symphysodon aequifasciatus, Symphysodon haraldi, Symphysodon discus, and Symphysodon tarzoo. These fish have specific care requirements, making them one of the most difficult fish to keep in home aquariums.
- Temperature: 82-86°F (27-30°C)
- pH Level: 5.5-7.5
- Water Hardness: soft to moderately hard
- Tank Size: minimum 50 gallons for a pair
- Tank Setup: dense vegetation, hiding places, and open swimming space
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230votes
Philippe Bourjon · CC BY-SA 3.0This fish is extremely sensitive to water quality and requires a varied diet of live and frozen foods. They are also prone to disease and need a lot of swimming space.The Moorish Idol (Zanclus cornutus) is an incredibly beautiful and highly sought-after saltwater fish. It is easily recognizable due to its unique and vibrant coloration, elongated body shape, and the characteristic long, trailing dorsal fin. The body of the Moorish Idol is predominantly white, adorned with bold black stripes and patches, and complemented by yellow fins.- Scientific Name: Zanclus cornutus
- Average Size: Up to 9 inches (23 cm)
- Lifespan: 5 to 7 years
- Tank Size: Minimum of 125 gallons
- Water Parameters: Temperature: 72-78°F (22-26°C), pH: 8.1-8.4, Salinity: 1.022-1.025
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327votesThese fish are challenging to keep because they require a specific diet of copepods and amphipods. They are also susceptible to disease and need a lot of hiding places in the tank.The Mandarin Dragonet (Synchiropus splendidus) is a small and colorful marine fish species known for its vibrant pattern and unique characteristics. It is a challenging species to keep in captivity due to its specific dietary requirements and sensitivity to water conditions.
- Size: Approximately 6 cm (2.4 inches) in length
- Habitat: Coral reefs and lagoons in the Pacific Ocean
- Diet: Primarily feeds on copepods and amphipods, requiring a well-established population of live food in the aquarium
- Tank Size: Minimum 75-gallon tank with ample hiding places and macroalgae for the fish to graze on
- Water Temperature: Should be maintained between 24-26°C (75-79°F)
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418votes
Harlequin Tuskfish (Choerodon fasciatus)
Georges CuvierThese fish are aggressive and require a large tank with plenty of hiding places. They also need a varied diet of meaty foods and are prone to disease.The Harlequin Tuskfish (Choerodon fasciatus) is a species of marine fish known for its striking appearance and complex care requirements. It was originally described by Lacepède in 1801 as Labrus fasciatus.- Scientific Name: Choerodon fasciatus
- Family: Labridae
- Size: Up to 12 inches (30 cm)
- Lifespan: 10-15 years
- Water Temperature: 75-82°F (24-28°C)
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516votesThese fish are challenging to keep because they require a large tank with pristine water quality. They also need a varied diet and are prone to disease.The Blue Tang (Paracanthurus hepatus) is a species of marine fish that is known for its vibrant blue coloration and distinctive yellow tail. It is commonly found in the Indo-Pacific region, particularly around coral reefs. This fish is popularly known for its appearance in the animated movie 'Finding Nemo' as the character Dory.
- Scientific Name: Paracanthurus hepatus
- Coloration: Vibrant blue body with a yellow tail
- Size: Can grow up to 12 inches (30 cm) in length
- Diet: Primarily herbivorous, feeds on algae and small invertebrates
- Habitat: Coral reefs in the Indo-Pacific region
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613votes
Photo by and (C)2007 Derek Ramsey (Ram-Man) · CC BY-SA 2.5Clown Triggerfish (Balistoides conspicillum)
Georges CuvierThese fish are aggressive and require a large tank with plenty of hiding places. They also need a varied diet of meaty foods and are prone to disease.The Clown Triggerfish (Balistoides conspicillum) is a species of triggerfish known for its colorful appearance and distinctive markings. It is native to the Indo-Pacific region, including the Red Sea and eastern Africa. This species was first described by the French naturalist Georges Cuvier in 1831.- Scientific Name: Balistoides conspicillum
- Maximum Size: Up to 20 inches in length
- Lifespan: Up to 10 years
- Habitat: Coral reefs and rocky areas
- Temperament: Aggressive
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711votes
Philippe Bourjon · CC BY-SA 3.0This fish is extremely sensitive to water quality and requires a varied diet of live and frozen foods. They are also prone to disease and need a lot of swimming space.The Moorish Idol (Zanclus cornutus) is an incredibly beautiful and highly sought-after saltwater fish. It is easily recognizable due to its unique and vibrant coloration, elongated body shape, and the characteristic long, trailing dorsal fin. The body of the Moorish Idol is predominantly white, adorned with bold black stripes and patches, and complemented by yellow fins.
- Scientific Name: Zanclus cornutus
- Average Size: Up to 9 inches (23 cm)
- Lifespan: 5 to 7 years
- Tank Size: Minimum of 125 gallons
- Water Parameters: Temperature: 72-78°F (22-26°C), pH: 8.1-8.4, Salinity: 1.022-1.025
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815votesThese fish are challenging to keep because they require a specific diet of copepods and amphipods. They are also susceptible to disease and need a lot of hiding places in the tank.The Mandarin Dragonet (Synchiropus splendidus) is a small and colorful marine fish species known for its vibrant pattern and unique characteristics. It is a challenging species to keep in captivity due to its specific dietary requirements and sensitivity to water conditions.
- Size: Approximately 6 cm (2.4 inches) in length
- Habitat: Coral reefs and lagoons in the Pacific Ocean
- Diet: Primarily feeds on copepods and amphipods, requiring a well-established population of live food in the aquarium
- Tank Size: Minimum 75-gallon tank with ample hiding places and macroalgae for the fish to graze on
- Water Temperature: Should be maintained between 24-26°C (75-79°F)
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97votes
Harlequin Tuskfish (Choerodon fasciatus)
Georges CuvierThese fish are aggressive and require a large tank with plenty of hiding places. They also need a varied diet of meaty foods and are prone to disease.The Harlequin Tuskfish (Choerodon fasciatus) is a species of marine fish known for its striking appearance and complex care requirements. It was originally described by Lacepède in 1801 as Labrus fasciatus.- Scientific Name: Choerodon fasciatus
- Family: Labridae
- Size: Up to 12 inches (30 cm)
- Lifespan: 10-15 years
- Water Temperature: 75-82°F (24-28°C)
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1011votesThese fish are challenging to keep because they require a specific diet of live foods and a slow current in the tank. They are also susceptible to disease and need a lot of care and attention.Seahorses (Hippocampus spp.) are unique and intriguing fish known for their distinctive appearance and behavior. These delicate creatures are characterized by their horse-like head, prehensile tail, and intricate patterned skin. They are fascinating creatures that have captured the attention of many fish enthusiasts.
- Size: Varies based on species; range between 0.6 to 14 inches (1.5 to 35 cm)
- Lifespan: Typically 1 to 5 years in the wild, with proper care they can live up to 10 years in captivity
- Habitat: Coral reefs, seagrass beds, and estuaries
- Water Parameters: Temperature: 72 to 78°F (22 to 26°C), Salinity: 1.020 to 1.025, pH: 8.1 to 8.4
- Diet: Primarily small crustaceans and zooplankton
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Discussion
Ranking factors for difficult fish
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Sensitivity and hardinessSome fish are more sensitive to water conditions and require very specific parameters to thrive. Their hardiness will determine how well they can handle fluctuations in their environment. They will need a stable water temperature, pH, and salinity.
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CompatibilityThe fish should be compatible with other tank mates, rather than being aggressive or territorial. Some fish are more likely to attack or eat other fish, while others are more peaceful and can coexist well.
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Size and growth rateConsider the adult size of the fish and how fast it grows to ensure that your aquarium will be large enough to accommodate them. Some fish can grow to be several feet long, which is not suitable for a small home aquarium.
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Diet and feeding requirementsSome fish have specific dietary requirements and may need live or frozen foods, making them more challenging to feed. Others might be picky eaters or require a specialized diet to stay healthy.
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Breathing requirementsSome fish, like labyrinth fish or catfish, need to gulp air from the surface to survive. These fish will require sufficient access to the surface and may not be suitable for densely planted or decorated tanks.
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Swimmer type and aquarium setupThe fish's swimming habits should be considered when setting up the aquarium. Some fish prefer to dwell near the bottom, others in the middle, and some at the top. The aquarium should have enough space, hiding spots, and the proper substrate for the fish to explore and feel comfortable in.
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Activity level and temperamentSome fish are very active and require a lot of space to swim and explore, while others are more sedentary and prefer a smaller, quieter environment. The fish's temperament should also be taken into account, as some fish are more prone to stress or aggression than others.
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Breeding behaviorsSome fish may be more challenging to keep in a community tank if they become aggressive or territorial during spawning or when caring for their young.
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Disease resistanceSome fish species are more susceptible to common aquarium diseases and may require more attention and care to prevent illness.
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Availability and priceSome fish are rare or difficult to find in the aquarium trade and may be expensive to purchase.
About this ranking
This is a community-based ranking of the most difficult fish to keep. We do our best to provide fair voting, but it is not intended to be exhaustive. So if you notice something or fish is missing, feel free to help improve the ranking!
Statistics
- 1843 views
- 177 votes
- 10 ranked items
Movers & Shakers
Voting Rules
A participant may cast an up or down vote for each fish once every 24 hours. The rank of each fish is then calculated from the weighted sum of all up and down votes.
More information on most difficult fish to keep
When it comes to keeping fish as pets, there are numerous factors to consider, such as the size of the tank, the water temperature, the type of food, and the compatibility of different species. However, some fish are notoriously difficult to care for, and require a high level of expertise and dedication.
One such fish is the discus, which is prized for its vibrant colors and graceful swimming, but is notoriously finicky about water quality and can be susceptible to a variety of diseases. Another challenging fish is the anglerfish, which requires live food and a very specific tank setup to thrive.
Other difficult fish to keep include the seahorse, which has a delicate digestive system and requires constant monitoring of water parameters, and the clownfish, which can be aggressive and territorial, and requires a carefully balanced diet of both live and frozen foods. Overall, keeping fish requires a lot of patience, knowledge, and attention to detail, and those who are up for the challenge will be rewarded with beautiful and fascinating creatures that can provide years of enjoyment.
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