A Guide to Choosing Freshwater & Saltwater Fish

Starting your first freshwater or saltwater aquarium is an exciting adventure, but selecting the right fish can seem daunting with so many beautiful options available.

 

You may be wondering which species you should start with, what is the proper tank size, their feeding schedules, proper water parameters, appropriate lighting levels, and more.

 

At Sanctuary Aquatics, we've guided countless beginners in creating beautiful freshwater and reef communities, and we're here to help you choose fish that are both stunning and beginner-friendly. We also can provide extensive information on proper fish care so that they can thrive in their new environment!

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Freshwater Fish Guide

Before exploring specific species, it's essential to understand what makes a fish "community-safe." These are fish that coexist peacefully with other species, don't exhibit excessive aggression, and have compatible care requirements.

 

These freshwater fish species typically don't harass smaller tankmates, destroy plants, or create territorial disputes that stress the entire aquarium.

4 Factors to Consider for Freshwater Tanks

1.) Tank Size and Bioload

Your aquarium's size is what ultimately determines your fish capacity. A general guideline we suggest is one inch of fish per gallon of water, though this will vary based on the species' waste production, activity level, and adult size. Remember that most fish will grow significantly from their juvenile size, so it's best not to overpopulate your tank with too many fish. At Sancuary Aquatics, we can guide you with the correct aquarium size and number of fish.

2.) Compatibility

As you consider compatibility, you should research each species' temperament and social needs. Peaceful community fish are ideal for beginners, while aggressive or territorial species can create stress and require more advanced management skills.

3.) Feeding Requirements

If you’re a complete beginner, we recommend that you select fish species with simple dietary needs. Species that readily accept high-quality flakes, pellets, and occasional frozen foods are much easier to maintain than those requiring live foods or specialized diets.

4.) Water Parameters

Lastly, consider that different fish have varying requirements for temperature, pH, and water hardness. Choosing species with similar needs simplifies maintenance and creates a more stable environment.

Top Beginner-Friendly, Community-Safe Fish

Tetras (Various species)

Neon Tetras, Cardinal Tetras, and Black Skirt Tetras are perfect schooling fish for beginners. They're peaceful, colorful, and thrive in groups of six or more. These small fish (1-2 inches) are hardy and accept a wide variety of foods. Their schooling behavior creates beautiful, dynamic displays in community tanks.

Betta (Betta splendens)

The brilliantly-colored Betta is a popular choice for many hobbyists. If you’re new to keeping Bettas, you should know that you will need to have one male in a separate, dedicated tank around 10-20 gallons, since males are quite territorial. Or you can house several female Bettas together. Males and females should be kept separate except for temporary breeding.

Corydoras Catfish (Corydoras species)

Bronze Cories, Panda Cories, and Albino Cories are excellent bottom-dwellers that help keep your substrate clean. They're peaceful, social fish that should be kept in groups of at least three. Their whiskers and bottom-feeding behavior add interesting activity to the lower levels of your aquarium.

Platies and Mollies (Poecilia species)

These livebearing freshwater fish are incredibly hardy and come in numerous color varieties. They're peaceful, easy to breed, and adapt well to various water conditions. Platies stay smaller (2-3 inches) while mollies can reach 4-5 inches.

 

Guppies (Poecilia reticulata)

Male guppies display brilliant colors and flowing fins, while females are more subdued but equally hardy. They're extremely adaptable, breed readily, and are perfect for beginners. Keep multiple females with each male to prevent harassment.

Danios (Danio species)

Zebra Danios and Giant Danios are active, schooling fish that add energy to your aquarium. They're incredibly hardy, tolerating a wide range of water conditions, and their constant movement creates visual interest. Keep them in schools of six or more.

Cherry Barbs (Puntius titteya)

These peaceful barbs are an excellent alternative to the more aggressive Tiger Barbs. Males develop beautiful red coloration, especially during breeding. They're schooling fish that remain relatively small and peaceful in community settings.

 

Gouramis (Smaller species)

Honey Gouramis and Dwarf Gouramis are beautiful, peaceful fish with labyrinth organs that allow them to breathe air from the surface. They're generally calm and work well in community tanks, though males can be territorial with each other.

Swordtails (Xiphophorus hellerii)

These active livebearers are named for the male's distinctive sword-like tail extension. They're hardy, colorful, and peaceful, making them excellent community fish. Like other livebearers, they're easy to breed and maintain.

Fish Species to Avoid as a Beginner

While these fish are popular and beautiful, they present challenges that make them more difficult for novice aquarists but are well suited for intermediate or advanced level hobbyists with more experience. Some of these species include:

• Cichlids (most species) can be highly territorial and aggressive, and require specific tank setups and careful species selection. Even "peaceful" cichlids often rearrange decorations and can stress community fish.
• African Cichlids require very specific water chemistry (high pH and hardness), specialized diets, and carefully planned communities. They're rewarding fish but require significant research and experience.
• Goldfish produce enormous amounts of waste, require cooler water temperatures than tropical fish, and grow much larger than most people expect. They're also messy eaters that can quickly pollute smaller tanks.
• Plecos (large species) like Common Plecos can grow over 12 inches long and produce massive amounts of waste. They also become more aggressive as they mature and may damage plants.
• Bettas (in community tanks) can be kept with other fish, but require careful species selection and plenty of space. Highly territorial with specific requirements, Bettas are typically better suited for dedicated tanks or more experienced hobbyists.
• Aggressive Barbs such as Tiger Barbs are fin-nippers that can stress peaceful community fish. They require specific tankmate selection and are better left to more experienced aquarists.

Building Your Freshwater Fish Community

When just getting started with the hobby, you can begin with one or two compatible species and observe their behavior and interaction before gradually adding more fish. This approach allows you to monitor water quality closely and ensure all inhabitants are healthy and stress-free.

 

Consider fish that occupy different levels of your aquarium – surface swimmers (like guppies), mid-water species (such as tetras and barbs), and bottom-dwellers (like corydoras catfish) create a more dynamic and visually interesting display while maximizing your tank's space efficiently.

Quarantine and Acclimation

Always quarantine new fish for at least two weeks in a separate tank before introducing them to your main aquarium. This step helps to prevent disease transmission and allows you to observe eating habits and overall fish health. Be sure to take your time with proper acclimation – gradually adjust new fish to your tank's temperature and water chemistry over several hours to minimize stress and shock.

Saltwater Fish Guide

 

At Sanctuary Aquatics, we've helped many beginners build their saltwater ecosystems, and we're here to guide you through selecting fish that are both beautiful and beginner-friendly. We also have a large selection of corals to add to your reef tank.

Understanding Reef-Safe Fish

Before diving into specific species, it's important to understand what makes a fish "reef-safe." These are fish that won't harm corals, invertebrates, or other tank inhabitants. They typically don't nip at coral polyps, hunt smaller tank mates aggressively, or disturb the delicate balance of a reef ecosystem.

4 Key Factors to Consider for Saltwater Tanks

1.) Reef Tank Size and Bioload

Your tank's size determines how many fish you can safely house. A good rule of thumb is one inch of fish per five gallons of water, though this varies based on the species' bioload (waste production) and activity level.

2.) Fish Compatibility

Research each species' temperament and territorial behavior. Peaceful community fish work best for beginners, while aggressive species can stress other inhabitants and are harder to manage.

3.) Notes on Feeding

Choose fish with straightforward dietary needs. Species that accept prepared foods like flakes, pellets, and frozen foods are much easier to care for than those requiring live or specialized diets.

4.) Understanding Water Parameters

Just like we discussed in the freshwater fish section, it's important to understand that different saltwater fish have varying requirements for temperature, salinity, and pH. Selecting species with similar needs simplifies maintenance and reduces stress on your reef community.

Top Beginner-Friendly, Reef-Safe Fish

Clownfish (Amphiprion species)

Clownfish are the perfect starter fish for marine aquariums. They're hardy, colorful, and relatively small, making them ideal for tanks as small as 20 gallons. Ocellaris and Percula clownfish are particularly beginner-friendly, accepting a wide variety of foods and adapting well to captive conditions. Their symbiotic relationship with anemones is fascinating to observe, though they'll thrive without one.

Cardinalfish (Apogon species)

Pajama Cardinals and Banggai Cardinals are peaceful, nocturnal fish that add gentle movement to your tank. They're excellent for community aquariums, rarely showing aggression toward other species. These fish prefer to school, so consider keeping them in small groups if your tank size allows.

Gobies (Various species)

Yellow Watchman Gobies and Neon Gobies are excellent choices for beginners. They're small, peaceful, and many species help with tank maintenance by eating algae or parasites. Watchman Gobies often form partnerships with pistol shrimp, creating an interesting dynamic in your aquarium.

Blennies (Various species)

Bicolor Blennies and Midas Blennies are charismatic fish with distinct personalities. They're generally reef-safe and help control algae growth. Their curious nature and amusing behaviors make them entertaining additions to any tank.

Wrasses (Smaller species)

Six Line Wrasses and Fairy Wrasses are beautiful, active fish that add color and movement to your reef. They're generally peaceful toward other species, though Six Line Wrasses can become territorial with other wrasses. These fish are excellent at controlling pest populations like flatworms and small crustaceans.

Royal Gramma

This stunning purple and yellow fish is both hardy and peaceful, making it perfect for beginners. Royal Grammas are cave-dwellers that appreciate rock work and hiding spots. They're completely reef-safe and rarely cause problems with other tank inhabitants.

Saltwater Species We Recommend Avoiding as a Beginner

While these fish are beautiful and popular in the hobby, they present challenges that make them unsuitable for novice aquarists first starting out with a saltwater tank:

• Mandarinfish require established tanks with abundant copepod populations and often refuse prepared foods, making them difficult to keep properly fed.
• Moorish Idols are notoriously difficult to keep in captivity, with specific dietary requirements and sensitivity to water quality changes that challenge even experienced aquarists.
• Large Angelfish like Queen Angels and Emperor Angels grow very large, require massive tanks, and can become aggressive as they mature. They also may nip at corals and clams.
• Triggerfish are highly intelligent but extremely aggressive, often reorganizing tank decor and bullying other fish. They also have powerful jaws that can damage equipment and tankmates.
• Seahorses require specialized care including specific water flow, feeding multiple times daily with live or frozen foods, and tanks designed around their unique needs.
• Pufferfish have complex dietary requirements, produce significant waste, and many species will eat invertebrates and smaller fish as they grow.
• Surgeonfish/Tangs (with exceptions) require large swimming spaces, excellent water quality, and can be prone to ich. Some smaller species like Yellow Tangs can work great for beginner and intermediate aquarists however!

What About Invertebrates?

 

Adding invertebrates to your saltwater aquarium introduces fascinating behaviors, unique colors, and beneficial tank maintenance functions:

• Starfish & Urchins: The colorful Fromia or Marble star make a striking addition, while Sea Urchins provide excellent algae control.
• Hermit Crabs: Excellent scavengers that help clean up leftover food and detritus while providing entertaining antics as they search for new shells.
• Cleaner Shrimp: Peppermint shrimp and Scarlet Skunk cleaners not only add vibrant colors but also provide valuable services by removing parasites from fish and cleaning algae from rocks.
• Sea Anemones: Create stunning focal points with their flowing tentacles and can form symbiotic relationships with clownfish, though they require stable water conditions and proper lighting.
• Soft Corals: Mushroom corals and Zoanthids are beginner-friendly options that add movement and color while being more forgiving than hard corals.
• Substrate Cleaners: For the substrate, sand-sifting creatures like Nassarius snails and fish like Sand-Sifting Gobies help maintain a clean tank bottom.

When selecting invertebrates, ensure compatibility with your fish species, as some fish may view smaller inverts as food.

Building Your Saltwater Fish Community

Start with two to three compatible species and observe how they interact before adding more fish. This gradual approach allows you to monitor water quality and ensure all inhabitants are thriving.

Consider the different water column levels your fish will occupy – having fish that swim at the top, middle, and bottom creates a more dynamic and visually appealing aquarium, a beautiful habitat that mimics the Great Barrier Reef!

Quarantine and Acclimation

Always quarantine new reef fish for at least two weeks before introducing them to your main tank. This prevents the spread of disease and allows you to observe the fish's health and eating habits. Proper acclimation is vital! Take time to slowly adjust new fish to your tank's water parameters.

Have Questions About Reef Fish Species? Contact Us!

 

At Sanctuary Aquatics, we believe that starting with hardy, compatible species sets you up for long-term success in the freshwater or marine aquarium hobby. Take time to research each fish thoroughly, plan your community carefully, and don't rush the stocking process.

 

Your patience will be rewarded with a thriving, beautiful reef aquarium that brings you years of enjoyment. Please contact our team at 920-385-4802 and we’ll help you set up your beginner tank!

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