New Zealand Temperate Marine Aquarium

        

Introduction to the Aquarium

I receive great pleasure from my recently established 160 litre New Zealand Temperate Marine aquarium, especially my two lovely female Seahorses. In addition to the Seahorses I have some native species of hard and soft corals.  We are truly fortunate in New Zealand to have such a spectacular variation of colours among the Jewel Anemone species (Corynactis), which is not an anemone like the common name suggest but a soft coral.

In September 2013 I started my first temperate marine aquarium that consisted of a 350 litre aquarium and a 300 litre sump, total water volume around 600 litres.  Now that I have a greater knowledge about native marine life and a greater appreciation, I plan to overhaul this aquarium and changed the aquascape to a more suitable permanent home for the seahorses and other companions.

This 160 litre aquarium is a temporary habitation for the seahorses while I set plans in place to overhaul the 600 litre temperate marine aquarium.  The following are the specifications of the aquarium:

• Marine Lighting: Medium to high, 10000K Cree LED
• Temperature: 16° C
• Salinity / Specific Gravity: 1.027
• Water Movement: Low to Moderate
• Substrate: Washed beach sand
• Hardscape: Coral rock, rocks with corynactis and shells
• Cooling and heating: ¼ HP Chiller, no heater
• Filtration: Biological media, activated carbon, protein skimmer and bio pellet reactor

Aquarium Maintenance and Equipment

I try not to over skim this aquarium as the Corynactis prefer a less pristine environment.  I do around 20% water changes per month, either by 5% weekly changes or 10% bi-weekly changes.  It is thought that proper magnesium levels are beneficial for the coral I have, however, I have not yet found a need to implement this.  Activated carbon is a good idea to reduce the toxins produced by the coral, particularly the Corynactis.  I have two Jebao WP-10 wave pumps pulsing at low speed and creating a flow from back to front that meets in the middle of the front glass.

Filtration is based on a modified Aqua One MariSys 240 system with hang-on overflow and priming pump.  Instead of running the MariSys independently it forms the drain and prefilter section within the sump tank.  This is achieved by removing the drain plug on the MariSys and allowing the water to flow through the media baskets and out into the sump tank itself where the skimmer, reactor and return pump reside.  Water first drains into the drip tray and then through wool pads before passing through the media baskets which are packed with crushed coral rock, ceramic balls and activated carbon. Once the water flows out from the MariSys canister it comes in contact with the protein skimmer and BioPellet reactor to remove waist from the water and keep the phosphate levels in check.  Water is returned to the aquarium above via a DC-2000 pump.

A simple auto top off canister is secured to the sump to ensure evaporated water is replace and that my salinity is maintained.  In order to keep the water temperature at 16 degrees Celsius a DC-1200 pump pumps water from the sump, through a small chiller and back into the sump.  An ITSA Cree LED light supplies light to the aquarium for 10 hours a day and is switched on and off by a 3in1 Programmable timer.

Pot-belly Seahorse (Hippocampus abdominalis)

Hippocampus abdominalis or Pot-belly seahorse are one of the largest seahorses, growing up to 35 cm in length. Seahorses are, despite their looks, a fish that swims in an erect position The head is held at right angles to the body, the eyes can move independently of each other and the tail is prehensile to enable them to hang on to objects. Instead of having scales, as most other fish, seahorses have a layer of skin stretched over bony plates that are visible as rings passing around the trunk.

The dorsal fin propels them forward and they steer using the pectoral fins on either side of the head. As the common name suggests this species has a large stomach. Their bodies are well camouflaged with colours in individuals ranging from brown, yellow, grey, white, orange or mottled, with dark spots and blotches on the head and body. Males differ from females in that they have a brood pouch, longer tails, and a shorter snout. The potbelly seahorse can live to 10 years in the wild and breed three times a year.

Usually found inhabiting harbours and sheltered coastlines amongst seaweeds around rocky areas in fairly shallow water, but can be found in deeper waters as well. They are more active at dusk and night than in the daytime spending most of the day anchored by their tail to rocks or weed.
Source http://aquariumworld.nz/forums/topic/29836-sea-horse-care-sheet/#comment-367915

They are not the easiest fish to feed as most require live foods, however my two are captive bred and have been transitioned over to frozen food.  They have a particular taste for mysid shrimp and brine shrimp, both frozen and live and finely chopped shrimp.

Corynactis (jewel anemone)

The Corynactis genus are basically a coral without a skeleton and their internal structures are the same as stony corals. These corals are closely related to stony corals and are less like anemones except for the fact that neither have a skeletal structure.  They can be variations of white, pink, red, orange, green, and clear.

The top of their body or the upper surface is called the oral disc. The stalk area, which is very small, is called the column and it is located just above the pedal disc which is where they attach to surfaces. They have feeding tentacles on the oral disk to capture prey each terminating in a small swelling of contrasting colours. The tentacles are arranged in rings around the mouth which is located at the top of a small cone on the oral disk.

They are moderate to difficult to care for and as there is not much information on the Corynactis species, following good husbandry methods with water quality, temperature and appropriate feedings are basic requirements. Corynactis are carnivorous and need to be fed small pieces of raw fish, shrimp, and mussel flesh. In addition to the food from feeding the seahorses I target feed the Corynactis once a week

I find that these Corynactis need nutrients to survive on and do not do well in a pristine environment like stony corals.  They are usually found underneath rocky overhangs or on vertical walls at various depths and often in groups of the same colour.  Most importantly they need a solid material to attach to which can also be shells as you can see in my aquarium.

Monomyces rubrum (cup coral)

Cup coral is the common name for solitary hard corals from the Cnidarians group of animals.  Some may look like a set of dentures as my ones do and others look more horn-shaped or have short flat disks.

In New Zealand, the majority of the hard corals are solitary and most of these occur in the deep sea but these cup coral are found in shallow water from 5 to 50 meters.  Cup corals usually attach to hard rocky substrates for vantage points to filter feed from with limited amounts of fine sediments to clog their filter-feeding apparatus.  Cup corals may also be found in an upright position extending beyond the surface of the surrounding soft sediments as I have done in my aquarium.

These Cup corals are protected by a delicate cup shaped skeleton of lime and protein.  They feed by extending their beautiful tentacles in search of prey and withdraw them when disturbed.  They need a constant supply of Phytoplankton and Zooplanktons or newly hatched Artemia (brine shrimp) to feed on.

Alcyonium aurantiacum (dead man’s fingers)

Alcyonium aurantiacum are also part of the Cnidarians group of animals and are classed as Octocorals because each polyp bears eight tentacles.  This is a true colonial soft coral that forms fleshy irregular masses which are finger like in appearance.  The polyps give the colony a feathery appearance and has earned them the name of ‘dead man’s fingers’.

Colonies of dead man’s fingers actively feed on plankton at various times of the day by extending their polyps and beating tiny hair-like cilia to generate water current. This brings food and oxygen into the polyp.

In the mornings I find my dead man’s fingers whith the polyps withdrawn and the fingers all shrivelled up.

Once the lights are on it slowly puffs up to 5 times the size and the polyps extend ready to feed.

Turbo smaragdus (Cat’s eye snail)

Cat’s eye is the common name for the lid or operculum of the common sea snail Turbo smaragdus which looks somewhat like an eye. When the snail is threatened by a predator or is exposed above the tide, it withdraws into its shell and the operculum seals the opening. After the snail has died and decomposed, the operculum falls free of the shell and is sometimes used for decorative purposes.

These are a great addition to the temperate aquarium and very efficient at eating algae off the glass and rocks.  Be careful of overstocking as this may cause them to starve and die, resulting in potential nutrient spikes.  If you intend keeping hermit crabs in your aquarium you need to be aware that they are quite capable of prying open the operculum and killing the snail.  Sometimes the hermit crab will moving house and into its victims shell.  Starfish will also feed on the smaller snails

Petrolisthes elongatus (Porcelain Crab)

The Porcelain Crab looks like a flattened large claw (chelae) crab. Its smooth blueish carapace is almost oval in shape but is slightly longer than it is broad, with only faintly marked regions and no spines. They are not a true crab as they have 3 pairs of walking legs instead of 4 pairs.  They are sometimes referred to as half crabs.  Porcelain crabs will readily shed claws and legs as an escape response.

The Porcelain Crab hides under rocks near low-tide level and is not often seen because it is well camouflaged.
Porcelain Crabs are filter feeders and feed by trapping food with a pair of mandibles equipped with a fine sieve on the mouth parts called a setae.  They waving their setae through the water within the protection of their big claws to capture passing planktonic food and draw it towards the mouth.

You would not know they are in my aquarium until feeding time when they come out to the edge of the rocks and comb the water for food.  I feed them on filter feeding food and switch between ReefPearls and Reef Chili.

Orange Starfish

I am not sure of the exact species of my orange starfish but I believe that it may be a young Sclerasterias mollis.  These starfish have five arms, sometimes six.  It feeds on molluscs with a hinged shell such as oysters, mussels and scallops.  Once the shell is open, the star pushes its stomach into the mollusc, secretes digestive enzymes, and absorbs its meal on the spot.

Starfish respiration works by sucking seawater in through tiny holes in a sieve plate on the upper surface.  This intake of seawater is also used to inflate the feet which often have suckers at the tip and serve as walking legs.

Starfish are famous for their ability to regenerate arms but what is less commonly known is that if the missing arm has a piece of the central disc of the starfish attached to it, then the arm will grow a new starfish. A large arm with a regenerating star is called a comet.

My starfish was collected by a diver in Dunedin and shipped to me in Auckland.  I have kept it for 2 years now and the little fellow or fellows as I will explain shortly, have been through some interesting changes.  12 months ago I came into my fish room one morning to feed the fish and I noticed my 6 legged starfish was missing one leg.  I searched the tank and found a single leg clinging to the coral rock.  This occurred in my 500 litre aquarium well before I set up this aquarium with the seahorses.  Later that evening I searched the aquarium for one-leg-less which it was now affectionately name and peg-leg the castoff leg, but neither could be found.  For two months I did not see one-leg-less or peg-leg so assumed the worst.  Then one night before lights out I was doing some work in the fish room and I saw a 5 legged starfish on the front glass, but there was something different about it.  It was much smaller than I remember.  Could this be a new starfish, peg-leg with 5 legs, and where was one-leg-less?  I have not been able to answer these questions as I have only ever seen the one smaller starfish since then.  I will hopefully find the answers when I overhaul my 500 litre aquarium.

Stenogramme interrupta (papery fan weed)

The common name for this red algae is papery fan weed which is rather appropriate when you see the fan like fronds.  This seaweed is found in coastal waters, almost exclusively subtidal and attached to rocks and stones.  They can be a little difficult to grow in the aquarium especially if there is not enough nutrients and light.  The fronds are delicate and can break off if thrashed around by high water flow so best not to position it in front of wave pumps.

Caulerpa brownii (Brown’s Caulerpa – Sea Rimu)

Brown’s Caulerpa is an erect emerald green algae commonly known as Sea Rimu in New Zealand because its fronds look very similar to the leaves of the Rimu tree.  This is a robust algae that looks like a chunky pipe cleaner tapered at the tip and with unbranched thin fronds.  The holdfast is a creeping horizontal runner with hair roots to anchor itself to the substrate.

Sea Rimu is commonly found just below low tide level, attached to rocks and in deeper pools exposed to waves on open coasts.  It can form sizeable beds and can give the appearance of moss-like textures.

In my aquarium it is anchored to a rock and placed in the current so that it waves gently back and forth.  It is very easy to grow and can spread rapidly in the right conditions.  Besides looking great in the aquarium it