A 75 gallon aquarium opens up a lot of exciting stocking options that aren’t possible in smaller tanks. With the proper setup and maintenance, a 75 gallon tank can comfortably house a wide variety of fish species and create a beautiful aquatic environment. But how many fish can you put in a 75 gallon tank? What are the best species to choose? Read on for a complete guide on setting up and stocking a 75 gallon freshwater aquarium.
How Many Fish in a 75 Gallon Tank?
The general rule of thumb is 1 inch of adult fish per 1 gallon of water. A 75 gallon tank can hold about 75 inches of fish at full capacity. However, this doesn’t mean you can or should keep 75 individual 1-inch fish in the tank.
Some key points to consider:
- Fish produce waste and need adequate swimming space. Overstocking causes poor water quality.
- Larger fish have a higher bioload than smaller fish.
- Active, schooling fish need more room than sedentary species.
- Combinations of species should be compatible in size and temperament.
- Aquascaping like plants and decor take up space and reduce total fish capacity.
- Filtration system capacity and maintenance schedule affect stocking levels.
- You want fish to thrive, not just survive! Quality over quantity.
Recommended Stocking for 75 Gallon Tank
Here are some general guidelines for stocking a 75 gallon tank while providing a healthy, balanced environment:
- Large fish (over 6 inches): 1-2
- Medium fish (3-6 inches): 4-6
- Small fish (under 3 inches): 15-25
- Bottom dwellers: 5-10
- Invertebrates/algae eaters: as desired
Table 1: Suggested Stocking Levels for a 75 Gallon Aquarium
| Fish Size | Number of Fish |
|---|---|
| Large (over 6″) | 1-2 |
| Medium (3-6″) | 4-6 |
| Small (under 3″) | 15-25 |
| Bottom dwellers | 5-10 |
| Invertebrates | as desired |
This would allow for around 75 total inches of fish, but gives them adequate swimming space and keeps bioload manageable. The actual stocking can vary based on your mix of fish.
Best Fish for a 75 Gallon Aquarium
Many species are well-suited for life in a 75 gallon freshwater tank. Consider the following criteria when selecting fish:
- Adult size and overall bioload
- Behavior and temperament
- Water parameter needs (temperature, pH, hardness)
- Level of care required
- Aquascape and tank placement preferences
Here are some excellent options to consider:
Large Fish
- Oscar
- Angelfish
- Discus
- Gourami
- Some Cichlids
Medium Fish
- Rainbowfish
- Guppies
- Mollies
- Platies
- Swordtails
- Zebra Danios
- Cherry Barbs
- Tetras
- Plecos
- Gouramis
Small Fish
- Neon Tetras
- Cardinal Tetras
- Harlequin Rasboras
- Zebra Danios
- White Cloud Mountain Minnows
- Endler’s Livebearers
- Corydoras Catfish
Bottom Dwellers
- Corydoras Catfish
- Plecos
- Loaches
Invertebrates/Algae Eaters
- Nerite Snails
- Mystery Snails
- Amano Shrimp
- Ghost Shrimp
- Bamboo Shrimp
75 Gallon Aquarium Setup
Before adding fish, you’ll need to set up a 75 gallon tank with all the proper components to maintain a healthy ecosystem. Here’s what to do:
Stand and Location
Choose a level stand that can safely support the weight of a 75 gallon tank when filled with water and decor (around 600-700 lbs). Place it away from direct sunlight and heating/cooling vents.
Tank
Select a good quality 75 gallon glass or acrylic aquarium. Make sure it comes with a lid or canopy to reduce evaporation.
Filtration
Install an external canister filter rated for at least 75 gallon tanks, or use multiple internal power filters that combined cycle at least 300 gallons per hour (GPH). This ensures adequate filtration for the tank’s fish capacity.
Heater
Use an aquarium heater appropriately sized for 75 gallons to maintain a stable water temperature. Choose a heater with temperature setpoint adjustment.
Substrate
Add 1-1.5 pounds of substrate per gallon of water. Gravel or sand are common options. Slope gently towards the back.
Decorations and Plants
Add structural elements like rocks, driftwood and non-sharp aquarium-safe decorations. Live or silk plants add enrichment. Arrange decor before filling with water.
Lighting
Pick an LED lighting system that supports live plants, if desired. Allow for 6-10 hours of light daily.
Fill Tank and Dechlorinate
Fill the tank with dechlorinated water. Use water conditioner to remove chlorine and chloramines. Check for leaks.
Cycle Tank
Cycle the tank to establish beneficial bacteria that process waste. Test ammonia and nitrite levels weekly. Perform partial water changes as needed.
Add Fish!
Once cycled, acclimate fish slowly by floating bags and adding small amounts of tank water. Turn off lights and release fish into the tank. Enjoy your new aquatic friends!
75 Gallon Aquarium Maintenance
Maintaining proper water quality is crucial for fish health. Perform these tasks regularly:
- Partial water changes: Replace 25-30% of the water weekly. Use a gravel vacuum to remove waste.
- Test water parameters: Check temperature, pH, ammonia, nitrite and nitrite levels weekly or as needed.
- Clean filtration: Rinse filter media monthly in old tank water to remove gunk and maintain beneficial bacteria.
- Algae control: Wipe down tank walls and scrub decor. Limit light exposure to 6-8 hours daily.
- Top off evaporated water: Add dechlorinated water as needed to replace evaporation.
- Gravel vacuuming: Deep clean substrate monthly to prevent waste buildup.
- Tank inspections: Observe fish health and behavior regularly. Watch for signs of disease or aggression.
- Equipment maintenance: Clean and calibrate gear like heaters, filters and test kits as needed.
Following this routine maintenance schedule helps provide optimal water quality and healthy tank conditions for your fish.
Key Water Parameters to Monitor
Keeping a close eye on your tank’s water parameters is essential for fish health and wellbeing. Here are 5 critical factors to monitor regularly:
Temperature
Use an accurate aquarium thermometer to ensure temperature stays stable and within your fish species’ preferred range. Rapid temperature swings can stress or kill fish.
pH
Test pH often, as levels above or below your fish’s desired range causes health issues. Adjust pH gradually if needed with products like pH Up or pH Down.
Ammonia
Ammonia from fish waste is highly toxic. Keep levels at 0 ppm through the nitrogen cycle. Use water changes, bacteria supplements, and biological media.
Nitrite
Nitrite occurs as ammonia converts to nitrate. Maintain under 0.5 ppm. It prevents oxygen transport in fish blood.
Nitrate
Keep nitrate under 40 ppm through partial water changes and nitrate-reducing filter media. High levels increase algae growth and harm fish health.
5 Most Common 75 Gallon Aquarium Fish Diseases
Even with excellent care, fish can sometimes fall ill. Here are 5 prevalent freshwater fish diseases to watch for:
Ich
Caused by the parasite Ichthyophthirius multifiliis. Fish develop white salt-like spots on skin and fins. Treat with anti-ich medications, higher heat, aquarium salt.
Fin Rot
Bacterial infection that causes frayed, rotting fins. Triggered by poor water quality. Improve conditions and use fin rot remedies, antibiotics. Separate sick fish.
Velvet
Another parasitic disease. Fish have rusty yellow “dust” on skin and lethargy, labored breathing. Treat with anti-parasitic meds.
Dropsy
Bacterial infection where fish bloat with fluid accumulation internally. Fish pinecone appearance. Can be fatal. Use Epsom salt, antibiotics.
Columnaris
Highly contagious bacterial disease. Shows cottony growths, rotting fins, skin ulcers. Use strong antibiotics, quarantine infected fish.
With prompt treatment, most fish infections are curable if addressed early. Always quarantine new fish. Reduce stress and maintain pristine water quality in your tank.
Conclusion
A 75 gallon aquarium provides the opportunity to create an impressive freshwater ecosystem. By following the 1 inch of fish per gallon rule, you can expect to house around 75 inches of fish total, in a combination of large, medium and small species compatible in size and temperament.
Perform regular partial water changes, test water parameters, and quarantine new fish. Providing a spacious, enriched environment allows fish to exhibit their natural behaviors. With responsible stocking and proper maintenance, a 75 gallon tank will bring you enjoyment for years to come!
Frequently Asked Questions about Stocking a 75 Gallon Tank
Can I put African cichlids in a 75 gallon aquarium?
Yes, a 75 gallon tank is a great size for many African cichlids like mbuna, peacocks and haps. Stock with 1 male for every 3-5 females of a species. Provide plenty of rocks and caves.
Are oscars suitable for a 75 gallon aquarium?
Oscars grow large but a single specimen would be fine long-term in a 75 gallon tank. Give them room to swim with a powerful filter and frequent water changes.
What fish can live with angelfish in a 75 gallon tank?
Good tank mates include medium tetras, rainbowfish, cory cats, dwarf gourami, and small plecos. Avoid fin nippers like tiger barbs.
Can you put a betta fish in a 75 gallon tank?
Absolutely! A 75 gallon tank would give a betta plenty of swimming space. Add leafy plants and hiding spots. Tankmates could include snails, shrimp and bottom feeders.
How many neon tetras in a 75 gallon aquarium?
You can comfortably house 20-25 neon tetras in a well-maintained 75 gallon tank. Keep them in a larger school of 8-10 fish minimum. Combine with other peaceful community fish.