Azure Damselfish
Pomacentridae
Semi-aggressiveReef safe
- Min tank
- 30 gallons
- Same species
- Can work, but expect a hierarchy
Reef Fish Compatibility Chart
Reef fish compatibility is the likelihood that saltwater species can share the same aquarium without chronic aggression, predation, or territory fights. This free saltwater fish compatibility checker compares common reef fish by temperament, tank size, and reef-safe behavior so you can build a calmer stocking plan.
Use the chart below to compare reef safe fish, spot territorial conflicts, and see which marine fish combinations deserve extra caution before you buy them.
Fish Database
Search 36 common reef fish and add them to your lineup.
36 species shown
Banggai Cardinalfish
Apogonidae
PeacefulReef safe
- Min tank
- 30 gallons
- Same species
- Good in pairs or groups
Bicolor Blenny
Blenniidae
Semi-aggressiveWith caution
- Min tank
- 30 gallons
- Same species
- Usually one per tank
Blue Green Chromis
Pomacentridae
PeacefulReef safe
- Min tank
- 30 gallons
- Same species
- Can work, but expect a hierarchy
Blue Tang
Acanthuridae
Semi-aggressiveReef safe
- Min tank
- 125 gallons
- Same species
- Usually one per tank
Carpenter's Flasher Wrasse
Labridae
PeacefulReef safe
- Min tank
- 30 gallons
- Same species
- Can work, but expect a hierarchy
Chalk Bass
Serranidae
PeacefulReef safe
- Min tank
- 30 gallons
- Same species
- Good in pairs or groups
Copperband Butterflyfish
Chaetodontidae
PeacefulWith caution
- Min tank
- 75 gallons
- Same species
- Usually one per tank
Coral Beauty Angelfish
Pomacanthidae
Semi-aggressiveWith caution
- Min tank
- 55 gallons
- Same species
- Usually one per tank
Diamond Watchman Goby
Gobiidae
PeacefulReef safe
- Min tank
- 40 gallons
- Same species
- Best as a single or bonded pair
Engineer Goby
Pholidichthyidae
PeacefulReef safe
- Min tank
- 125 gallons
- Same species
- Can work, but expect a hierarchy
Firefish Goby
Microdesmidae
PeacefulReef safe
- Min tank
- 20 gallons
- Same species
- Best as a single or bonded pair
Flame Angelfish
Pomacanthidae
Semi-aggressiveWith caution
- Min tank
- 70 gallons
- Same species
- Usually one per tank
Flame Hawkfish
Cirrhitidae
Semi-aggressiveWith caution
- Min tank
- 30 gallons
- Same species
- Usually one per tank
Foxface Rabbitfish
Siganidae
PeacefulWith caution
- Min tank
- 125 gallons
- Same species
- Usually one per tank
Kole Tang
Acanthuridae
Semi-aggressiveReef safe
- Min tank
- 70 gallons
- Same species
- Usually one per tank
Lawnmower Blenny
Blenniidae
PeacefulReef safe
- Min tank
- 40 gallons
- Same species
- Usually one per tank
Longnose Hawkfish
Cirrhitidae
Semi-aggressiveWith caution
- Min tank
- 30 gallons
- Same species
- Usually one per tank
Lyretail Anthias
Serranidae
PeacefulReef safe
- Min tank
- 70 gallons
- Same species
- Good in pairs or groups
Mandarin Dragonet
Callionymidae
PeacefulReef safe
- Min tank
- 50 gallons
- Same species
- Best as a single or bonded pair
Maroon Clownfish
Pomacentridae
AggressiveReef safe
- Min tank
- 55 gallons
- Same species
- Best as a single or bonded pair
Melanurus Wrasse
Labridae
Semi-aggressiveReef safe
- Min tank
- 55 gallons
- Same species
- Usually one per tank
Midas Blenny
Blenniidae
PeacefulReef safe
- Min tank
- 30 gallons
- Same species
- Usually one per tank
Neon Goby
Gobiidae
PeacefulReef safe
- Min tank
- 10 gallons
- Same species
- Good in pairs or groups
Ocellaris Clownfish
Pomacentridae
Semi-aggressiveReef safe
- Min tank
- 20 gallons
- Same species
- Best as a single or bonded pair
Orchid Dottyback
Pseudochromidae
Semi-aggressiveReef safe
- Min tank
- 30 gallons
- Same species
- Usually one per tank
Pajama Cardinalfish
Apogonidae
PeacefulReef safe
- Min tank
- 30 gallons
- Same species
- Good in pairs or groups
Percula Clownfish
Pomacentridae
Semi-aggressiveReef safe
- Min tank
- 20 gallons
- Same species
- Best as a single or bonded pair
Purple Firefish
Microdesmidae
PeacefulReef safe
- Min tank
- 20 gallons
- Same species
- Best as a single or bonded pair
Royal Gramma
Grammatidae
PeacefulReef safe
- Min tank
- 30 gallons
- Same species
- Usually one per tank
Six Line Wrasse
Labridae
AggressiveReef safe
- Min tank
- 30 gallons
- Same species
- Usually one per tank
Tailspot Blenny
Blenniidae
PeacefulReef safe
- Min tank
- 20 gallons
- Same species
- Usually one per tank
Tomini Tang
Acanthuridae
Semi-aggressiveReef safe
- Min tank
- 70 gallons
- Same species
- Usually one per tank
Yellow Coris Wrasse
Labridae
PeacefulReef safe
- Min tank
- 50 gallons
- Same species
- Can work, but expect a hierarchy
Yellow Tang
Acanthuridae
Semi-aggressiveReef safe
- Min tank
- 75 gallons
- Same species
- Usually one per tank
Yellow Watchman Goby
Gobiidae
PeacefulReef safe
- Min tank
- 30 gallons
- Same species
- Best as a single or bonded pair
Your Lineup
Add fish, then compare the compatibility chart below.
Start with a sample lineup or add species from the database to generate a live marine fish compatibility report.
Try a Sample
Overall fit
Compatible
Add fish to score compatibility.
Selected fish
0 species
Build a lineup from the database.
Recommended minimum tank
Not set
Based on the largest minimum tank requirement selected.
Warnings found
0
Includes pair conflicts, same-species issues, and tank warnings.
Want to save your final fish plan? Track livestock, water tests, and maintenance in My Reef Log.
Compatibility Matrix
Compare each selected species against every other fish in your list.
CompatibleUse CautionHigh Risk
Add at least one fish from the database to populate the reef fish compatibility chart.
Warnings and Notes
Review aggression, same-species, and tank-size warnings before you stock.
The warning feed updates live once you add fish to the lineup.
Pair-by-Pair Report
Use this report to see why each combination is marked as compatible, caution, or high risk.
Add at least two different species to generate pair-by-pair compatibility notes.
How To Check Saltwater Fish Compatibility
1
Add the fish you want to compare
Search the built-in reef fish database and add each species to your lineup.
2
Adjust quantity and enter your tank size
Set how many of each fish you plan to keep and optionally enter your tank volume in gallons.
3
Review the compatibility chart
Use the matrix to spot compatible pairs, caution pairs, and high-risk mixes at a glance.
4
Read the warnings before you stock
Check aggression notes, same-species issues, reef-safe cautions, and tank-size warnings before you buy livestock.
Frequently Asked Questions
Are reef-safe fish always compatible with each other?
No. Reef safe only means a fish is less likely to damage corals or invertebrates. Many reef-safe fish still fight over territory, bully shy species, or clash when two similar fish want the same part of the tank.
Can you keep more than one tang in the same reef tank?
Sometimes, but tank size matters. Tangs often compete for algae and open swimming space, so a mixed tang lineup usually needs a long tank, careful introduction order, and fish with different body shapes when possible.
Does tank size change fish compatibility?
Yes. A larger aquarium creates more territory, more escape routes, and less constant visual contact. Fish that barely coexist in a 75 gallon tank may settle much better in a 180 gallon system with broken lines of sight.
Which reef fish are usually best for peaceful community tanks?
Firefish, cardinalfish, clownfish pairs, gobies, chromis, and many watchman gobies are common starting points. Even then, you still need to watch same-species aggression, feeding style, and minimum tank size before adding them together.
Related Reef Tools
Aquarium Volume Calculator
Find your true water volume before you compare fish tank size requirements.
Dosing Calculator
Plan supplement adjustments after stocking changes and heavier feeding.
Salt Mix Calculator
Figure out exactly how much salt mix you need for water changes.
Fish Tank Stocking Calculator
Estimate bioload and safe stocking level once your fish list looks compatible.
Water Parameter Calculator
Check if nitrate, phosphate, salinity, and temperature suit the fish you chose.
Build the Fish List, Then Track the Tank
My Reef Log helps you keep the fish you choose healthy over time by tracking livestock, maintenance, water tests, and long-term parameter trends in one place.