Description
Yellowtail Damselfish (Chrysiptera parasema)
- Temperament: Semi Aggressive
- Care Level: Easy
- Reef Safe: Yes
- Max size: 2.75″ or 7 cm
Overview
The Yellowtail Damselfish (Chrysiptera parasema), also known as the Yellowtail Demoiselle or Goldtail Damsel, is a vibrant, small marine fish native to the Indo-Pacific region, including areas like Indonesia, the Philippines, and the Great Barrier Reef. It inhabits shallow, coastal reefs, lagoons, and rubble areas at depths of 1-15 metres, where it often hides among algae-covered rocks and seagrass. In aquariums, this species is popular among beginners and intermediate hobbyists due to its hardiness, striking appearance, and relatively peaceful nature compared to other damselfish. Adults typically exhibit a bright yellow tail contrasting against a blue body, while juveniles may show a more uniform blue coloration with a developing yellow tail. Males and females are similar in appearance, but males can develop a more intense blue hue during breeding. This fish is reef-safe with caution, as it may nip at small-polyp stony corals (SPS) or feather dusters if underfed or stressed. It grows to a maximum size of about 6.5 cm (2.5 inches) in length, making it suitable for nano to medium-sized aquariums.
Care Requirements
Yellowtail Damselfish thrive in well-established marine aquariums that mimic their natural reef environment. Key parameters should be stable and monitored regularly. Below is a summary of essential care requirements in metric measurements:
Parameter Recommended Range Notes
Tank Size Minimum 38 litres (10 US gallons) for a single specimen; 95-114 litres (25-30 US gallons) for a small group Larger tanks help reduce aggression; nano tanks (under 57 litres) are possible but require excellent filtration.
Temperature 24-27°C (75-81°F) Use a reliable heater and thermometer; fluctuations can stress the fish.
pH 8.1-8.4 Maintain with regular water changes and buffering if needed.
Salinity/Specific Gravity 1.020-1.025 (33-35 ppt) Use a refractometer for accuracy; RO/DI water is ideal for mixing saltwater.
Ammonia/Nitrite 0 ppm Essential for health; test weekly.
Nitrate Below 20 ppm (ideally <10 ppm) Keep low through frequent water changes and live rock.
Water Flow Moderate to strong (10-20x tank volume per hour) Simulates reef currents; use powerheads to prevent dead spots.
Lighting Moderate to high (6-8 hours/day) LED or T5 fluorescents suitable for reef setups; supports algae growth if desired.
Water quality is paramount—perform 10-20% weekly partial water changes to maintain parameters. The tank should be cycled for at least 4-6 weeks before adding the fish. Provide plenty of live rock or coral rubble for hiding and perching, as this species is semi-aggressive and territorial.
Maintenance
Routine maintenance is straightforward for this hardy species but crucial to prevent common issues like ich (a parasitic disease) or fin rot.
Filtration: Use a protein skimmer, hang-on-back (HOB) filter, or canister filter rated for the tank size. Add activated carbon or chemical media monthly to polish water.
Substrate and Decor: 5-7 cm of fine sand or aragonite substrate with 10-20 kg of live rock per 100 litres for biological filtration and natural behaviour. Avoid overcrowding—start with 1-3 specimens to establish a hierarchy.
Cleaning: Siphon detritus during water changes; clean filter media as needed without disrupting beneficial bacteria. Quarantine new fish for 2-4 weeks in a 38-57 litre setup to check for parasites.
Common Issues: Watch for aggression during feeding or breeding; signs of stress include faded colour or rapid gill movement. Treat ich with copper-based medications (in a hospital tank) or freshwater dips if needed, but avoid in main display if corals are present.
Lifespan: 5-8 years with proper care; monitor for overfeeding, which can lead to obesity or water fouling.
This fish is forgiving of minor parameter swings but benefits from a mature, stable system.
Diet
Yellowtail Damselfish are omnivores with a preference for meaty foods in captivity, though they naturally graze on algae and small invertebrates. Feed small amounts 2-3 times daily to mimic natural foraging, ensuring all food is consumed within 5 minutes to avoid pollution.
Primary Diet: High-quality marine flakes or pellets (e.g., containing spirulina for colour enhancement). Offer frozen or live foods like brine shrimp, mysis shrimp, copepods, or cyclops.
Variety: Supplement with chopped seaweed (nori clips) or blanched vegetables like spinach for fibre and vitamins. Avoid beefheart or tubifex worms, as they can cause nutritional imbalances.
Feeding Tips: Use a turkey baster to target-feed in community tanks. Juveniles may require more frequent meals; adults can go 1-2 days without food if needed. Vitamin supplements (e.g., Selcon) can be soaked into foods weekly for optimal health.
A balanced diet promotes vibrant colours and active behaviour.
Behaviour and Compatibility
Yellowtail Damselfish are generally peaceful but can become territorial, especially as they mature or in pairs/groups. They are active swimmers, often darting among rockwork and schooling loosely in larger tanks. In the wild, they form small harems, so keeping 3-5 together can reduce bullying of subordinates.
Behaviour: Diurnal (active during the day); they perch on substrates and may “dance” or flare fins during courtship. Semi-aggressive—males defend nesting sites aggressively. They are hardy acclimators and quick to adapt but may stress slower fish with constant activity.
Compatibility:
Good Tankmates: Other peaceful damselfish (e.g., Azure or Lemon Damsels), clownfish, gobies, blennies, chromis, and small wrasses/shrimp. Invertebrates like snails, hermit crabs, and non-stinging anemones are usually safe.
Avoid: Aggressive species like large angelfish, triggers, or dottybacks, which may bully them. Also, avoid very small nano fish or delicate shrimp if the damsel shows nipping tendencies.
Reef Compatibility: Generally safe but may pick at LPS corals or feather dusters; monitor in mixed reefs.
Stocking Tip: Introduce in groups to the largest tank first to establish pecking order. Single specimens can become overly bold and bully newcomers.
Overall, they add movement and colour to community setups without dominating.
Reproduction
Yellowtail Damselfish are substrate spawners and relatively easy to breed in home aquariums, especially in a species-specific 57-95 litre tank with stable parameters. Breeding success is higher in groups of 1 male to 2-3 females.
Sexing: Difficult visually; males are slightly larger (up to 6.5 cm) and more intensely blue during spawning, with a more pointed dorsal fin.
Breeding Setup: Provide flat rocks, PVC pipes, or ceramic tiles as spawning sites. Maintain temperature at 25-26°C and feed protein-rich foods to condition breeders.
Spawning: Occurs in the evening; the male courts the female, leading her to deposit 200-500 adhesive eggs on the substrate (up to 3 mm diameter). The male fertilises and guards the clutch, fanning it for oxygenation and removing debris. Hatching takes 2-3 days at 25°C, with larvae becoming free-swimming after 3-5 days.
Rearing: Larvae require rotifers or newly hatched brine shrimp for 7-10 days, then transition to larger foods. Infusoria or greenwater can help. Survival rates are low (10-30%) without experience, but survivors grow quickly.
Tips: Remove the female after spawning to prevent egg-eating. Water quality must be pristine—ammonia spikes can wipe out fry. Bred specimens are hardy and can be sold to local stores.
With patience, this species can be a rewarding breeder for marine enthusiasts. Always research local regulations for captive-bred marine fish.
Picture for illustrative purposes only. Either come in store to view available stock or request pictures to be sent to you.
Please Note: Due to variations within species resulting from age, region, sex, etc., the actual livestock may not look identical to the image. Approximate size range may also vary between individual specimens.
