Saltwater · Intermediate · 20+ gal

Ocellaris clownfish

Amphiprion ocellaris

Ocellaris clownfish are among the more forgiving marine fish, but they still need a cycled saltwater tank, stable salinity, and marine-level testing. A 20-gallon tank can house a pair; 30 gallons is more comfortable.

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Care parameters for Ocellaris clownfish
Water type	Saltwater
Care level	Intermediate
Minimum tank	20 gallons
Temperament	A bonded pair is usually peaceful in a reef or FOWLR tank. They may be territorial around a host anemone or a favored rock. Do not mix with large aggressive marines that will hunt them.
Diet	Omnivore. Frozen mysis, brine, chopped seafood, and a quality marine pellet or frozen prep. Feed small amounts once or twice daily. They will also pick at some detritus and pods.
Temperature	74–78 °F
pH	8–8.4
Hardness / salinity	Marine salinity around 1.024–1.026 specific gravity. Alkalinity, calcium, and magnesium matter more in reef tanks than GH in the freshwater sense.

Captive-bred, still a marine tank

Amphiprion ocellaris is captive-bred in huge numbers and is often the first saltwater fish people keep. The fish is relatively hardy. The aquarium is not: you still need a nitrogen cycle, marine salt, a hydrometer or refractometer, and usually live rock or a dedicated biological filter.

A 20-gallon saltwater setup can work for a pair of ocellaris in a well-maintained nano reef or FOWLR (fish-only with live rock). Thirty gallons is more stable. Hold the water at 74 to 78°F with an adjustable heater. They are intermediate because of saltwater husbandry, not because the fish is fragile.

Anemones are optional

Clownfish do not require an anemone to thrive. Hosting is natural and beautiful, but anemones need strong, appropriate lighting, stable parameters, and often a larger, mature tank. Buying a bubble-tip anemone on day one of a new nano is a common way to kill an expensive invertebrate.

Let the tank mature. If you add a host later, research that species. Many 'carpet' anemones are poor beginner choices and can sting other livestock.

Pairs and sex

Clownfish are protandrous hermaphrodites: the largest in a group becomes female. A typical home pair is two fish that have sorted themselves. Adding a third adult to a small tank often means bullying. Buy two juveniles and let them pair, or buy an established pair.

Tank mates

Peaceful community wrasses, gobies, and firefish in an appropriately sized reef
A pair of ocellaris together is typical; extra adults can fight
Anemones are optional and have their own lighting and husbandry needs
Avoid large groupers, triggers, and aggressive marines

Gear for this fish

A few listings we would open for this species. Skip anything you already own that still works.

Instant Ocean Sea Salt, 50 gallons
Captive-bred clownfish still live in saltwater. This is the mix a lot of fish-only and beginner marine tanks actually use. Mix it in a bucket, not in the display.
Skip Reef Crystals if you are running fish-only with live rock and not chasing coral numbers. You still need a hydrometer or refractometer. Never dump salt on livestock.
See this listing
Hikari Marine-S pellets
A pair of ocellaris will take a small marine pellet as a staple, plus frozen mysis. Soft, sinking Marine-S is sized for smaller marine fish, not tangs.
Feed small amounts once or twice a day. Skip this if they already eat a quality marine pellet. Frozen mysis still belongs in the rotation. Anemones are optional; food is not.
See this listing
Coralife Deep Six hydrometer
Salinity is the number freshwater kits will not give you. A swing-arm hydrometer is cheap, widely available, and good enough to mix salt and keep it in range.
Tap out bubbles before you read it, and rinse it after. Skip this if you already own a calibrated refractometer. Target about 1.024–1.026 specific gravity.
See this listing

Frequently asked questions

Do clownfish need an anemone?+

No. They do well without one. Anemones are a separate, more demanding animal.

What size tank for ocellaris clownfish?+

A well-run 20-gallon can house a pair. 30 gallons is a more comfortable, stable start for a first marine tank.

Are clownfish beginner saltwater fish?+

They are a reasonable first marine fish if you already understand cycling, salinity, and testing. They are not a shortcut around saltwater basics.

Next step

Planning a tank for these?

Plan on 20 gallons or more. Put your actual tank size into the stocking calculator and it shows what else can live alongside them.

Open the stocking calculator

Before you buy

Beginner saltwater aquarium setup: Salt, cycling, and the order to buy things before the first fish.
Refractometer: Salinity creeps up as water evaporates. This is how you catch it.
Water test kit: Tells you when the cycle is done and when a water change is due.

Keep your fishies swimming.

Related species

Saltwater · Intermediate

Firefish goby

Nemateleotris magnifica

Firefish gobies are elegant, hovering dartfish for a covered saltwater tank. A 20-gallon reef can work for one. The lid is not optional. They jump.

Min. tank: 20 gal

Care notes →

Saltwater · Intermediate

Yellow tang

Zebrasoma flavescens

Yellow tangs are active Hawaiian surgeonfish that need swimming room, not a nano reef. A home-aquarium minimum is about 125 gallons with length to patrol and rock to graze.

Min. tank: 125 gal

Care notes →