Fish Lab & Aquaria – Marine Life in the Maldives

Large Aquarium

There have been no changes in our main display aquarium during January, and all species and corals continue to do well.

Jellyfish – Aurelia aurita

The sump system continues to work well, with no losses and minimal shrinking of the specimens in our large Kreisel display cylinder. Water changes are maintained at 35% every two days, with a larger water change when required.

Plankton Production

Plankton production remains consistently good. The algae are continuing steadily on a four-day turnover. One of the 100L algae buckets was contaminated with rotifers, so a third rotifer culture has been started. Due to a delayed delivery of Nanno3600, the feeding of the rotifers was kept to a minimum, resulting in a gradual decrease in numbers. Since the order arrived, regular feeding has resumed, and Rotifer numbers have started to increase again.

Following the arrival of the new microalga (unicellular diatom Thalassiosira weissflogii), we are attempting to rear Artemia to adult stage in smaller 20L buckets to free up resources.

Ornamental Fish Breeding

• Common clownfish (Australia) (Amphiprion ocellaris) – The larvae continue to do well and have been relocated to a glass-fronted display tank. We have also created a ‘fake anemone’ using rubber bands to encourage natural hosting behaviours in the young before introducing them to a real anemone. The breeding pair have been removed from their enriched diet to slow egg production.
• Clark’s clownfish (Amphiprion clarkii) – At the start of January, we removed the egg clutch to prevent predation.
  Day 5 – the high waterflow rearing tank unexpectedly triggered early hatching, and the larvae were observed swimming while consuming the yolk sac.
  Day 7 – some eggs became anoxic; the remaining viable eggs were allowed to float freely around the tank (closed system, high aeration, lights off). Most eggs hatched prematurely overnight, but the larvae were lost due to stress.
  Using a lower flow rate resulted in anoxia; returning to the parental tank resulted in consumption. More experimentation is needed to perfect our removal and rearing process.
• Maldivian clownfish (Amphiprion nigripes) – The December egg clutch was successfully collected upon hatching using the larval snagger. The larvae survived well for two weeks, before a system malfunction resulted in mortality.
• Peacock damsel (Pomacentrus pavo) – The newly arrived diatoms will be used as food for future larvae.
• Humbug damselfish (Dascyllus aruanus) – displaying mating behaviours, so we have introduced a PVC breed pipe to their tank.
• Sexy shrimp (Thor amboinensis) – new arrivals (two females, one male).
• Coral-banded shrimp (Stenopus hispidus, female) – continues to feed well, but moulted incompletely, and is now regenerating limbs.
• Seahorse (Hippocampus kuda) – started to develop a brood pouch and will hopefully begin breeding shortly.

Small Marine Aquara

Three new juvenile fish specimens, found as part of our frame relocation work, were introduced to our aquaria:

• Dusky farmerfish (Stegastes nigricans),
• Bird wrasse (Gomphosus varius), protogynous species,
• Humbug damselfish (Dascyllus aruanus), protogynous species.

Aquarium One

• Mini coral frame – all fragments are healthy and growing.
• Sea star (Linckia multifora) – continues to be healthy.
• Maldivian clownfish (Amphiprion nigripes) – laid eggs on the aquarium wall, behind their anemone. It’s only a small clutch of small, pale eggs.

Aquarium Two

• Mini coral frame – all fragments are healthy.
• Clark’s clownfish (Amphiprion clarkii) – laid in their preferred spot (CCA-covered rock); the eggs look healthy, large and pigmented.
• Blue damselfish (Chromis viridis) – laid eggs on a partially shaded area on the wall of the aquarium, behind a rock. The eggs are very small in size, in a 10cm patch, aerated by the largest parent.
• Mushroom corals – regularly moved by the resident crabs
• Coral-banded shrimp (Stenopus hispidus) – healthy and feeding well.

(A) Amphiprion clarkii (aquarium #2) with eggs in early developmental stage.
(B) Amphiprion nigripes (aquarium #1) eggs in late developmental stage.
[C] Chromis viridis (aquarium #2) eggs in early developmental stage.