Start your first saltwater aquarium! Equipment, cycling, first fish, and maintenance for FOWLR and reef tanks.
meerwasser · 9 Min. Lesezeit · saltwater, marine, beginner, FOWLR, reef
Marine aquariums are stunning, but they require more knowledge, equipment, and maintenance than freshwater. Here's how to start successfully.
Freshwater: Simple (pH, GH, KH)
Saltwater: Complex (salinity, alkalinity, calcium, magnesium, phosphate, nitrate)
Marine fish are less forgiving of parameter swings.
Freshwater: Filter, heater, light
Saltwater: Protein skimmer, powerheads, refractometer, RO/DI water system, test kits
Budget: Saltwater costs 2-3× more upfront.
Freshwater: Weekly water changes, simple
Saltwater: Weekly water changes + water testing + top-offs (evaporation) + equipment cleaning
Freshwater fish: €2-20 per fish
Saltwater fish: €15-100+ per fish
Corals: €20-200+ per colony
Yes, if:
Start with freshwater first if:
Easiest saltwater setup.
Livestock:
Pros:
Best for: Saltwater beginners
Most challenging but most rewarding.
Livestock:
Pros:
Cons:
Best for: Experienced hobbyists
Focus on a single species or group.
Examples:
Best for: Specialists with specific interests
Minimum: 100L (25 gallons)
Ideal: 200L+ (50+ gallons)
Why bigger?
Avoid nano tanks (<40L) as a beginner — extremely unstable!
Removes dissolved organic waste before it breaks down into nitrate.
Essential for saltwater!
Types:
Sizing: Rated for 1.5-2× your tank volume
Recommended brands: Reef Octopus, Bubble Magus, Tunze
Porous rock colonized by beneficial bacteria.
Functions:
Amount: 0.5-1kg per liter of water
Cost: €5-15 per kg
Curing: If buying "uncured" rock, cure it in a separate container for 2-4 weeks (smells terrible!)
Marine tanks need strong water flow (10-20× tank volume per hour).
Why?
Example:
Brands: Tunze, Hydor, Jebao
Marine fish need 24-27°C (75-80°F).
Use 1 watt per liter (or 2 heaters for redundancy).
Titanium heaters recommended for saltwater (won't corrode).
FOWLR: Basic LED (fish don't need intense light)
Reef tanks: High-intensity LED or T5
Recommended: AI Prime, Kessil, Radion, Orphek
Measures salinity precisely (more accurate than hydrometers).
Target salinity: 1.025-1.026 specific gravity (35ppt)
Cost: €20-50
Tap water contains phosphates, nitrates, and metals — toxic for marine tanks!
RO/DI (Reverse Osmosis / Deionization) system:
Cost: €80-200 for home unit
Alternative: Buy RO/DI water from LFS (€0.50-1 per liter)
Brands: Instant Ocean, Red Sea Coral Pro, Tropic Marin
Amount: ~35g salt per liter of RO/DI water
Cost: €15-50 per 10kg bucket (makes 300L)
Essential tests:
Reef tanks also need:
Recommended: Salifert, Red Sea, Hanna Checkers (digital)
Same nitrogen cycle as freshwater, but slower (6-8 weeks typical).
Bacterial starters help: Dr. Tim's One & Only, Microbacter7
Pros: Extremely hardy, cheap (€5-15)
Cons: Aggressive (remove before adding delicate fish)
Pros: Hardy, iconic, captive-bred available
Cons: Can be territorial (especially pairs)
Pros: Colorful, small, hardy
Cons: Semi-aggressive
Pros: Peaceful, beautiful
Cons: Shy, needs tight-fitting lid (jumps!)
Pros: Schooling fish (group of 5+), peaceful
Cons: Can be nippy in small groups
Go slow! Marine tanks are sensitive to sudden bioload increases.
Add 1 fish every 2-4 weeks.
Example 200L FOWLR stocking:
Research compatibility! Many marine fish are territorial.
Wait! Uncycled marine tanks kill fish fast.
Use RO/DI only — tap water causes algae outbreaks and phosphate spikes.
Patience! Add fish slowly or face ammonia spikes.
Always quarantine new fish 2-4 weeks — marine diseases spread fast.
Stagnant water = poor oxygenation and algae growth.
Saltwater aquariums are challenging but incredibly rewarding.
Start with:
Once you master FOWLR, upgrade to beginner corals (Zoanthids, Mushrooms, Leathers).
Marine fishkeeping is a journey — start simple, learn, and grow!