To Keep Marine Fish:

• Choose the right tank: A larger tank is more stable, so choose the largest one you can accommodate, ideally 250 liters or more. 
• Install equipment: Set up the heater, filter, and a protein skimmer. A wavemaker can also be beneficial for water circulation. 
• Add substrate and rock: Rinse live rock and place it in the tank, then add substrate like aragonite or crushed coral. Live rock provides a habitat for beneficial bacteria. 
• Mix saltwater: Use RO water and a marine salt mix, following the manufacturer's instructions. You can pre-mix it in a separate container with a powerhead and heater. 
• Fill and start: Gently fill the tank with the mixed saltwater, turn on the filter and heater, and start the nitrogen cycle. This can take about a month, and you must wait until ammonia and nitrite levels are zero before adding fish. 
• Daily and weekly maintenance
  • Daily:
    • Check the water temperature to ensure the heater is working correctly. 
    • Top off the tank with RO water to replace evaporated water. 
    • Inspect the tank for any signs of stress in the fish. 
  • Weekly:
    • Perform a partial water change (10-20%) with pre-mixed saltwater. 
    • Test water parameters like salinity, pH, nitrate, and phosphate. 
    • Clean the tank walls and scrub the filter media if needed. 
    • Empty the protein skimmer collection cup. 
• Feeding and stocking
  • Feed sparingly: Feed fish daily, but avoid overfeeding, which can foul the water. Some species may require frozen or live foods instead of flakes. 
  • Stock wisely: When adding fish, do so gradually. Research potential tank mates to avoid predatory or aggressive species. 
  • Consider a clean-up crew: Add-in algae-eating fish or invertebrates like snails to help keep the tank clean. 

1. Equipment and setup     

• Tank size: Choose a tank of at least 50 gallons (190 liters) to provide more stable water parameters.  
• Filtration: A fish-only tank needs robust filtration, including a protein skimmer to remove organic waste.  
• Substrate: Use live sand and marine-safe rock to aid in biological filtration and provide hiding places for fish.  
• Water movement: Use powerheads to ensure adequate water movement.  
• Lighting: While high-intensity lighting isn't as crucial as for a reef tank, it's still needed to set the mood. LED lighting is a good energy-efficient option.  
• Saltwater: Use RO water to mix with a high-quality marine salt mix to achieve a specific gravity between 1.0231.023 and 1.0261.026.  

• Back in fashion: Fish-Only Saltwater Tanks - Fishkeeping News13 Oct 2019 — Put good quality live rock in the sump, where it will grow beneficial algae, sponges and even critters if you don't run...Fishkeeping News
• How To Setup A Saltwater Tank For Beginners (No Skimmer)15 Jul 2022 — I'm using a cut to size aquarium leveling mat that will even off the last millimeter or so of angle. and because the ta...YouTube · Reef Dork1mReef DorkYouTube·15 Jul 2022

  How To Setup A Saltwater Tank For Beginners (No Skimmer)

  YouTube·Reef Dork·15 Jul 2022YouTube

            2. Cycling and stocking     

• Cycling: Before adding fish, the tank must be fully cycled. This establishes beneficial bacteria that convert waste products into less harmful substances.  
• Adding fish: Introduce fish slowly to avoid overwhelming the biological filter. Research species to ensure compatibility, as some fish-only tanks may house semi-aggressive or predatory species.  
• Clean-up crew: Consider adding a "clean-up crew" of snails and hermit crabs to help control algae.  

• FOWLR, Fish Only with Live Rock, Reef Tank - FishloreAs the name implies, this saltwater fish only tank setup is really for keeping fish only. You may be able to keep a few snails or ...Fish Lore
• How to Set up a Saltwater Aquarium - Bulk Reef Supply12 Jun 2023 —  * Find a suitable location. Place the aquarium where it will be appreciated on a daily basis and is easy to access for...Bulk Reef Supply

            3. Maintenance     

• Water changes: Perform regular water changes (e.g., 10-15% weekly) to keep pollutants low and mineral levels stable.  
• Top-offs: Marine aquariums lose water to evaporation. Top off the tank daily with fresh, un-salted RO water to maintain salinity.  
• Cleaning: Clean equipment like protein skimmers and filter media regularly to ensure they are functioning correctly.

Choosing marine fish

• Hardy, beginner-friendly options: Consider species like the Ocellaris Clownfish or Blue-green Chromis, which are known to be hardier and easier to care for. 
• Consider tank size and compatibility: Different species have different needs. For example, Pajama Cardinalfish can live alone in a 10-gallon tank, while other fish require larger spaces and specific tank mates. 
• Research before buying: Always research the specific requirements of any fish you plan to keep to ensure they are a good fit for your tank and your experience level. 

Why marine fish cannot live in freshwater

• Physiological differences: Marine fish have a much higher concentration of body fluids than freshwater fish. In a freshwater environment, this can cause water to rush into their bodies, increasing blood volume and pressure to a fatal level. 
• Oxygen levels: Freshwater has less oxygen than saltwater, making it difficult for marine fish to get the oxygen they need to survive and adding to their stress. 

1. Equipment and setup     

• Tank size: Choose a tank of at least 50 gallons (190 liters) to provide more stable water parameters.  
• Filtration: A fish-only tank needs robust filtration, including a protein skimmer to remove organic waste.  
• Substrate: Use live sand and marine-safe rock to aid in biological filtration and provide hiding places for fish.  
• Water movement: Use powerheads to ensure adequate water movement.  
• Lighting: While high-intensity lighting isn't as crucial as for a reef tank, it's still needed to set the mood. LED lighting is a good energy-efficient option.  
• Saltwater: Use RO water to mix with a high-quality marine salt mix to achieve a specific gravity between 1.0231.023 and 1.0261.026.  

• Back in fashion: Fish-Only Saltwater Tanks - Fishkeeping News13 Oct 2019 — Put good quality live rock in the sump, where it will grow beneficial algae, sponges and even critters if you don't run...Fishkeeping News
• How To Setup A Saltwater Tank For Beginners (No Skimmer)15 Jul 2022 — I'm using a cut to size aquarium leveling mat that will even off the last millimeter or so of angle. and because the ta...YouTube · Reef Dork1mReef DorkYouTube·15 Jul 2022

  How To Setup A Saltwater Tank For Beginners (No Skimmer)

  YouTube·Reef Dork·15 Jul 2022YouTube

            2. Cycling and stocking     

• Cycling: Before adding fish, the tank must be fully cycled. This establishes beneficial bacteria that convert waste products into less harmful substances.  
• Adding fish: Introduce fish slowly to avoid overwhelming the biological filter. Research species to ensure compatibility, as some fish-only tanks may house semi-aggressive or predatory species.  
• Clean-up crew: Consider adding a "clean-up crew" of snails and hermit crabs to help control algae.  

• FOWLR, Fish Only with Live Rock, Reef Tank - FishloreAs the name implies, this saltwater fish only tank setup is really for keeping fish only. You may be able to keep a few snails or ...Fish Lore
• How to Set up a Saltwater Aquarium - Bulk Reef Supply12 Jun 2023 —  * Find a suitable location. Place the aquarium where it will be appreciated on a daily basis and is easy to access for...Bulk Reef Supply

            3. Maintenance     

• Water changes: Perform regular water changes (e.g., 10-15% weekly) to keep pollutants low and mineral levels stable.  
• Top-offs: Marine aquariums lose water to evaporation. Top off the tank daily with fresh, un-salted RO water to maintain salinity.  
• Cleaning: Clean equipment like protein skimmers and filter media regularly to ensure they are functioning correctly.