Clownfish are the easiest marine fish to breed at home. They pair up reliably, spawn predictably, and the fry can be raised on cultures you can produce yourself. If you've ever wanted to try marine breeding, this is the species to start with.
This guide covers the basics: getting a pair, setting up the system, raising fry, and the timeline you should expect.
Getting a breeding pair
Clownfish are sequential hermaphrodites. They start out non-sexual and develop into either male or female depending on social cues. The largest fish in a group becomes female, the second-largest becomes male, and the rest stay non-sexual.
Two ways to get a pair:
- Buy a known pair. Look for two clowns with a clear size difference, ideally already spawning.
- Buy two juveniles and let them sort it out. Cheaper but slower. Two young clowns of the same species will pair within a few months.
Stick to common species (A. ocellaris and A. percula) for your first attempt. They spawn freely, accept cheap food, and the fry are easier to raise than designer morphs or rarer species.
Setting up the breeding tank
You don't need anything fancy. A 60 to 100 L bare-bottom tank works well. Setup:
- Hang-on-back filter or sponge filter
- Heater set to 26 to 28°C
- One clay tile or terracotta pot for the pair to lay eggs on
- An optional anemone (BTA or rose) as a host. Not required, but encourages more reliable spawning.
- Stable water parameters. Salinity 1.024 to 1.026, ammonia and nitrite zero, nitrate under 20 ppm.
Skip live rock. It traps eggs and makes egg removal harder when the time comes.
Encouraging spawning
Once the pair is settled, conditioning increases your odds:
- Feed two to three times per day with high-quality food. Mix frozen mysis, pellets, and live or enriched brine shrimp.
- Maintain stable temperature. Sudden swings stress the pair.
- Mimic a regular photoperiod. 12 hours on, 12 hours off.
- Be patient. Most pairs take two to three months to start spawning, and some take longer.
Once spawning starts, expect a clutch of 100 to 1,000 eggs every 12 to 14 days.
Hatching the eggs
Eggs take 7 to 9 days to hatch at 26°C. Hatching always happens at night, around an hour after lights out.
The standard approach is to remove the egg-laying surface (tile) on the night you expect hatching and place it in a separate larval rearing tank with gentle aeration aimed at the eggs. The fry hatch into the rearing tank, where you have full control over the food supply.
Raising the fry
Newly hatched clownfish fry are tiny and need live food immediately. The standard sequence:
- Day 1 to 7: rotifers. Cultures must be dense and fed live phytoplankton continuously. The water should look slightly green (greenwater technique).
- Day 5 to 14: rotifers and live copepod nauplii. Transition phase.
- Day 10 to 21: enriched live brine shrimp nauplii. Newly hatched, gut-loaded with phyto.
- Day 18 onwards: frozen and dry foods. Most clowns metamorphose around day 8 to 12 and are weaning onto crushed pellets by day 18.
Without rotifers, you can't raise clownfish. Plan your culture or order schedule before the eggs hatch, not after.
Common problems
- Pair won't spawn. Usually a conditioning issue. More food, stable parameters, give them time.
- Eggs fungus over. Dad isn't tending them properly. Sometimes happens with first-time pairs. They usually figure it out by the second or third clutch.
- Fry die at day 3 to 5. Almost always a food issue. The rotifer culture wasn't dense enough, or the larvae weren't accepting them.
- Fry settle but won't eat. Try smaller copepods (Apocyclops nauplii) and live brine shrimp before frozen.
The bottom line
Clownfish breeding is rewarding, achievable, and a brilliant introduction to marine aquaculture. The hardest part isn't the fish, it's the food chain. Get your rotifer and live phyto cultures dialled in before the eggs hatch, and the rest follows.
