Have you ever stopped and thought about how awesome pet fish are? If your mind instantly goes to a tiny goldfish in a bowl—think again! Remember the stunning underwater world in Finding Nemo? Or the mesmerizing ocean scenes in Aquaman? Fishkeeping isn’t just about small tanks and basic fish—it’s an entire underwater universe waiting to be explored. Some fish, like Oscars, grow over a foot long, and angelfish? Their fins stretch even taller, making them look absolutely stunning in the right setup.

If you’re just starting out, you’ll probably go for something small and easy to care for—totally understandable! But once you get hooked (pun intended), it’s hard not to want something a little more unique. Experienced fishkeepers are always on the lookout for exciting new species, and while classics like the Ocellaris clownfish (yep, "Nemo") are popular, there are so many other fascinating options out there.

But here’s the thing—keeping these fish happy isn’t as simple as tossing them into a tank and calling it a day. The demands of various fish vary, and some need special attention. To maintain everything just perfectly, we're talking about large tanks (think 55+ gallons), exact water conditions, and even cutting-edge equipment. It may seem like a lot, but I promise it will be well worth it once you see these fish in action.

We'll explore some of the most well-liked fish among seasoned aquarists, along with their unique characteristics and all the information you need to take good care of them. You're in for a treat, so stay put whether you're interested in improving your fishkeeping skills or are simply interested in learning more about exotic fish.

Picking pet fish takes a different approach once you move past the beginner stage. New aquarium parent often chooses fish based on their colors and looks. Experienced fish keepers know that successful aquarium management needs a more thoughtful selection process.

Experience-based selection criteria

Advanced aquarists look at specific traits before adding new fish to their tanks. They assess vital factors like the fish's full-grown size, territorial nature, and how well it gets along with other tank residents. They also think about whether a species needs company or prefers to be alone, as this affects tank dynamics and the fish's well-being.

Veteran fish keepers pay attention to breeding potential and genetic diversity. Fish domestication needs careful selection to boost their productive traits and help them adapt to new environments. Expert aquarists want to develop specific characteristics through selective breeding, such as better growth rates and stronger resistance to environmental shifts.

Understanding fish behavior patterns

Expert pet fish keepers know that fish behavior links directly to their natural adaptations. Fish see their world through sight, smell, hearing, touch, taste, and specialized lateral line water-current detectors. Advanced aquarists create environments that support these sensory needs.

Species communication is vital to tank harmony. Fish use visual and chemical signals, and some species release specific chemicals called pheromones to communicate. Expert keepers can spot behaviors that show stress or illness. Unusual swimming, hiding for long periods, or staying near the surface often points to problems with water quality or tank dynamics.

Advanced care capabilities

Expert fish keepers shine at handling complex care needs. They know some species need specific conditions, like particular substrate depths or special feeding schedules. They have the expertise to care for fish that are hard to feed or need expert-level care.

Advanced aquarists excel at:

• Watching for subtle behavior changes that might show health issues

• Handling species-specific diet needs

• Keeping water parameters exact

• Understanding different life stages' unique requirements

Expert keepers often work with fish that present unique challenges in parasite control or moving stress. These fish aren't impossible to keep, but long-term success needs deep knowledge and dedicated care routines.

Years of experience help advanced fish keepers develop a natural feel for their aquatic pets' needs. They understand that successful fishkeeping goes beyond simple maintenance and covers deep knowledge of species' behaviors, environmental needs, and potential health issues. This complete approach helps them keep challenging species and build thriving aquatic ecosystems.

Pro Tip: Feeding your fish a balanced, high-quality diet is key to their health and longevity. Whether you’re caring for a picky electric blue ram or an active Odessa barb, choosing the right food makes all the difference. Check out Supertails' collection of premium  fish food  to keep your fish in top shape!

Expert aquarists love fish species that challenge them and reward their efforts. These hobbyists know complex species need precise care, dedication, and deep knowledge of aquatic ecosystems.

Hardy yet challenging species

1. Discus fish 

•  Lifespan:  10–15 years

•  Size:  Up to 8 inches

•  Temperament:  Peaceful but territorial

•  Water Conditions:  Soft, warm (82–86°F), low pH

Why They're Amazing

Discus fish are the showstoppers of freshwater tanks. With their round bodies, stunning colors, and graceful movements, they look more like  floating pieces of artwork  than actual fish. They come in shades of electric blue, deep red, golden yellow, and mesmerizing patterns that shift in the light.

But Here's the Catch

Discus fish are not for the casual fishkeeper. They’re incredibly sensitive to changes in water quality, temperature, and even stress. Think of them like  divas —they demand the best and will sulk (or worse) if conditions aren’t just right. You’ll need to do frequent water changes, maintain  crystal-clear water , and make sure they’re eating a  high-protein diet  to keep them in top shape.

But if you’re willing to put in the work?  You’ll have one of the most breathtaking aquariums around. 

2. Electric Blue Ram

•  Lifespan:  3–4 years

•  Size:  2–3 inches

•  Temperament:  Peaceful but shy

•  Water Conditions:  Warm (78–85°F), soft, acidic (pH 5.5–7.0)

•  Tank Size:  20 gallons minimum

Why They're Amazing

If you want a fish that literally glows, meet the  electric blue ram . Their scales shimmer in shades of blue, almost like they have built-in LED lights. They’re peaceful, curious, and full of personality—once they warm up to their environment.

But Here's the Catch

These little guys are  water quality snobs . Skip just one water change, and you’ll see their colors fade, their energy drop, and possibly even lose them. They need  perfectly clean water , steady temperatures, and absolutely  zero  ammonia or nitrite spikes. They’re also pretty shy, so they do best with  calm tank mates  and plenty of hiding spots.

3. Pearl Gourami

•  Lifespan:  4–5 years

•  Size:  4–5 inches

•  Temperament:  Peaceful, interactive, intelligent

•  Water Conditions:  Moderate (75–82°F), slightly acidic to neutral (pH 6.5–7.5)

•  Tank Size:  30 gallons minimum

Why They're Amazing

If you want a fish that’s both  gorgeous and smart , look no further than the  pearl gourami . Their delicate pearl-like spots and long, flowing fins give them a truly elegant look. But the coolest part? These fish actually  recognize their owners  and can even learn to eat from your hand!

But Here's the Catch

While pearl gouramis are adaptable, they still need  a well-planted tank and calm tank mates . They’re  air breathers , meaning they’ll sometimes come up to the surface to gulp air, so make sure they have access. They also don’t like loud or aggressive fish, so keep them with peaceful species that won’t stress them out.

4. Congo Tetra

•  Lifespan:  3–5 years

•  Size:  3–4 inches

•  Temperament:  Active, peaceful, loves to school

•  Water Conditions:  Hard water (73–82°F), neutral to alkaline (pH 6.5–7.5)

•  Tank Size:  40 gallons minimum (Best in schools of 6+)

Why They're Amazing

Congo tetras are  like swimming rainbows . Their iridescent scales constantly shift between blue, purple, gold, and green, making them one of the most dazzling tetras out there. They also have  flowing, translucent fins  that add to their beauty.

But Here's the Catch

These guys  need space . They’re schooling fish, so keeping just one or two isn’t an option—they need a  group of six or more  to feel secure. They also prefer  dim lighting and a planted tank , which makes their colors pop even more.

5. Odessa Barb

•  Lifespan:  5–7 years

•  Size:  2.5–3 inches

•  Temperament:  Active, semi-aggressive

•  Water Conditions:  Wide range (72–78°F), soft to hard (pH 6.0–8.0)

•  Tank Size:  30 gallons minimum (Best in groups)

Why They're Amazing

If you want a fish that’s  bold in both personality and color , the  Odessa barb  is perfect. Their  fiery red stripes and dark contrast markings  make them stand out, and they’re  constantly on the move , adding tons of energy to any tank.

But Here's the Catch 

Odessa barbs are  active —sometimes too active. They can be a little pushy, so they’re best kept with fish that can handle their high energy (avoid slow or long-finned species). They’re also happiest in  groups of at least six , where they’ll establish a pecking order and keep each other entertained.

Explore further:  Understanding Fish Food: A Key to Fishkeeping Success

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Rare and unique varieties

The aquarium hobby has seen rising interest in distinctive fish that break the mold of typical pets.  Lake Kutubu rainbowfish dazzle viewers with their turquoise backs and silvery-yellow bellies in larger tanks. These 4-inch beauties excel in alkaline conditions, making them ideal for experts with specialized setups.

 Galaxy Rasboras from Myanmar  offers another spectacular choice. Dark blue bodies decorated with pearl-like spots and vibrant red fins give them an otherworldly look. These peaceful schooling fish need well-maintained planted tanks to thrive.

 The Platinum Arowana stands as proof of expert breeding success. This ghostly pale variety differs from true albinos and can cost up to INR 33,752,180.32. Expert keepers value them beyond their looks - these fish need extensive specialized care knowledge.

 Brazil's Xingu River gives us the Zebra Pleco , another gem for advanced aquarists. These eye-catching black-and-white striped catfish grow 2.5 to 4 inches long and have become rare as their natural habitat faces threats. Responsible aquarists prefer to get captive-bred specimens.

Expert fish keepers know these sophisticated species require:

• Precise water parameter management

• Advanced feeding techniques

• Specialized tank setups

• Deep understanding of species-specific behaviors

These challenging yet rewarding species continue to fascinate advanced aquarists. They provide opportunities to advance aquarium keeping expertise while supporting conservation efforts.

Pet fish enthusiasts now have amazing new ways to care for complex species thanks to technological breakthroughs. Smart systems and automation help aquarists provide the best care possible for their aquatic friends.

Smart aquarium systems

Expert aquarists now select and maintain pet fish differently because of advanced IoT-based monitoring solutions. These systems use strategically placed sensors to collect immediate data that helps control aquarium conditions precisely. Aquarists can check tank parameters and get instant alerts about condition changes through mobile apps.

Digital twins mark a revolutionary step forward. Fish keepers can now test and perfect different scenarios in simulation before making actual changes to their systems. This feature becomes particularly valuable when adding new species or tweaking environmental settings.

Water quality monitoring tools

Clean water conditions are vital for fish health, which explains why experts now depend on advanced monitoring equipment. Modern sensors track essential parameters continuously. Dissolved oxygen must stay above 4 parts per million (ppm) to keep fish healthy. Fish can die when levels drop below 1 ppm, so constant monitoring becomes essential.

Automated monitoring happens much more frequently than old manual testing methods and offers these benefits:

• Changes in water chemistry show up immediately

• Critical parameters get tracked multiple times daily

• Extreme conditions and short-term patterns become measurable

These sophisticated tools help aquarists create stable environments for delicate species. To cite an instance, electrical conductivity sensors employ time domain reflectometry technology to measure multiple parameters at once.

Automated feeding solutions

Success in fishkeeping depends heavily on precise feeding management. Modern automated feeders work together with smart monitoring systems to deliver the right nutrition based on what each species needs. These systems prevent both excess and insufficient feeding by giving exact portions at set times.

The newest feeding technology uses artificial intelligence to check fish growth and calculate proper food amounts. Some systems even employ deep learning computer vision to spot feeding patterns and adjust food distribution.

Cloud-based platforms let aquarists:

• Set up feeding schedules for specific species

• Track how much food gets eaten

• Change portions based on live data

• Match feeding with other tank activities

These automated solutions reduce wasted food while making feed conversion more efficient. The systems can automatically stop feeding during water changes or when conditions aren't ideal by working with water quality monitors.

Also Read:  Types of Fish Food: Pros and Cons of Different Options 

Pet fish keeping success depends on understanding skill levels. Aquarists develop their knowledge to care for complex species as they gain more experience.

Beginner-friendly options

New fish keepers should pick hardy species that can survive common mistakes. Level 1 fish can handle changing water conditions and minor care oversights.  White Cloud Mountain Minnows  are perfect starter fish that adapt to different temperatures and stay small at 1.5 inches long.

 Platies  are great choices for newcomers because they're active and adapt to different water parameters.  Neon Tetras  work well for beginners too. These fish stay under 1.5 inches and bring bright colors to community tanks.

Intermediate challenges

Level 2 and Level 3 fish need more detailed care. These species can handle different pH and hardness ranges but react badly to ammonia and nitrite. Cherry Barbs fit this category well. They show off beautiful red colors in planted tanks but need more careful attention.

Aquarists at this level must know how to:

• Monitor water parameters regularly

• Keep filtration systems clean

• Meet specific dietary needs

• Handle territorial behaviors

Bolivian Rams show intermediate complexity well - these peaceful cichlids need stable water conditions and show interesting social behaviors. Harlequin Rasboras need close attention to their schooling habits and stable environments.

Expert-level species

Level 4 and 5 fish test the skills of experienced aquarists with complex needs. These fish need constant attention to waste management and exact water parameters. Discus fish are a prime example that needs precise water conditions and special feeding schedules.

Some species are expert-only because of unique challenges:

•  Dietary complexities  - some angelfish and Moorish Idols have trouble with long-term nutrition

•  Environmental demands  - Garden Eels need 6 inches of fine sand and a specific water flow

•  Parasite susceptibility - Acanthurus tangs, like Powder Blue and Powder Brown types, catch parasites easily due to thin slime coats

Expert-level fish often struggle during transport. Their survival depends on proper acclimation. Species like Octocinclus need clean water and specific foods, including algae tablets and fresh vegetables.

Expert keepers must be skilled at:

• Complex feeding schedules

• Precise water chemistry

• Spotting species-specific stress signs

• Preventive health care

Aquarists can move through these skill levels with good preparation and learning. The path from beginner to expert takes patience, dedication, and a steadfast commitment to learning each species' needs.

Pet fish need the right space and water conditions to thrive. A good setup and proper maintenance will help your aquatic friends live well in captivity.

Tank size considerations

The right tank size creates the foundation for successful fish keeping. A gallon of freshwater weighs 8.34 pounds (3.785 kilograms), and strong structural support is vital. New aquarists should start with tanks no smaller than 20 gallons (80 Liters). Tanks of 29-30 gallon (~120 Liter) will give even better stability.

Experienced keepers look beyond volume and focus on the tank's footprint - its length and width dimensions. Wider tanks are better than taller ones because they:

• Give fish more swimming space to exercise

• Create better surface area for gas exchange

• Make aquascaping easier

• Keep water conditions more stable

Decorations and substrate take up 10-15% of the nominal tank capacity. Your calculations for stocking levels should factor in this reduced space.

Water parameter requirements

The right water chemistry is vital for fish health. Oxygen levels in the water must stay above 4 ppm - levels below 1 ppm can kill fish. You should check these key water parameters often:

• pH: Most freshwater fish do well between 6.5-8.5

• Alkalinity: 50-300 ppm keeps pH stable

• Ammonia: Keep levels under 0.5 ppm

• Nitrite: Should be zero for best health

• Temperature: Usually 20°C to 30°C (68°F to 86°F)

New aquarists should wait 24-48 hours before adding fish to freshwater tanks. Saltwater setups need longer cycling - at least three days but a week is better. The specific gravity should measure between 1.020-1.025.

Good filtration helps maintain water quality. Your filter systems should cycle the tank's total volume four times every hour. To cite an instance, a 10-gallon aquarium needs a filter that handles at least 40 gallons per hour.

Advanced keepers should think about carbonate hardness (KH) and general hardness (GH). These measurements show the water's buffering capacity and mineral content. Regular testing with quality aquarium test kits prevents sudden changes that might stress your fish.

A careful approach to space and chemical requirements lets aquarists create environments where pet fish species can thrive. The right setup ended up determining whether any aquarium succeeds, which makes these factors significant for both new and experienced fish keepers.

You just need more than simple knowledge and colorful fish to succeed at fish keeping. Our research and experience show that expert aquarists excel by matching their skill levels with suitable fish breeds and using advanced technology to manage care precisely.

Becoming skilled at fish keeping takes commitment to complex species behaviors, exact water parameters, and perfect tank environments. Challenging species like Discus fish or Platinum Arowana need sophisticated care routines. These remarkable creatures are a great way to get rewards for experienced keepers.

Advanced monitoring systems and flexible solutions make fish care more manageable. Notwithstanding that, technology complements rather than replaces expert knowledge. Successful aquarists blend modern tools with deep understanding of their chosen species' needs.

Note that fish-keeping expertise grows step by step. Hardy species suited to your current skill level work best for beginners. You can progress toward more challenging varieties as your knowledge expands. This measured approach helps you and your aquatic companions thrive together.

What is the cheapest fish in India?

If you’re looking for affordable pet fish in India, here are some of the best budget-friendly options:

• Goldfish (Common or Comet): ₹50–₹150 per fish. They are easy to find but require a properly filtered tank , not just a bowl.

• Guppies: ₹30–₹100 per fish. Hardy, colorful, and ideal for beginners.

• Mollies & Platies: ₹40–₹120 per fish. Available in different colors and patterns.

• Zebra Danios: ₹30–₹80 per fish. Super hardy and great for community tanks.

• Neon Tetras: ₹50–₹120 per fish. Small, schooling fish that add a vibrant touch to any aquarium.

What is the smallest pet fish?

If you’re looking for tiny fish that can thrive in small tanks, here are some of the smallest pet fish breeds:

• Paedocypris (World’s Smallest Fish): A rare fish found in Indonesia, growing only 0.3 inches (7.9mm) long.

• Dwarf Pea Puffer: One of the smallest freshwater puffers, growing to just 1 inch . Needs a planted, species-only tank .

• Chili Rasbora: A beautiful nano fish, reaching just 0.7 inches in length. Best in groups.

• Endler’s Livebearer: A close relative of the guppy, these fish grow to around 1 inch and thrive in nano tanks.

• Celestial Pearl Danio (Galaxy Rasbora): A stunning tiny fish that maxes out at 0.8–1 inch .