SMALLER SYSTEM SPECIES — UP TO 125-LITRES

SEAHORSES

6Scientific name: Hippocampus sp.

6Distribution: Circumtropical (many temperate species occur)

6Price range: £35-100+

6System size: Can be very small by marine fish standards; 90-litres is a practical size for many and there are sump based systems out there of this sort of size that are almost ideal for a pair or two of the smaller readily available species of seahorse.

Seahorses are perhaps the most widely kept marine fish in species-only aquaria. There are many aquarists who maintain them alongside other (often quite sedate) species, but this can be a problem due to the individual characteristics of these enigmatic fish.

Seahorses are slow feeders. Even captive bred fish that readily to accept food from an aquarist’s fingertips need to be overfed to ensure they receive sufficient rations. They are vulnerable to stings from corals and anemones and may damage corals by wrapping around them with their prehensile tails — they aren’t exactly reef compatible and don’t do well with boisterous competitors.

In a species-specific set-up you’ll find seahorses a lot easier to care for than you might otherwise think. Settled individuals can mooch around unmolested and pick frozen mysids from the base of the aquarium, resulting in far less demand for excess feeding and all of the potential issues that it can cause — particularly when a small display aquarium is used, keeping the food in close proximity to the seahorses at all times.

Kept well, seahorses offer aquarists so much; they are unique amongst fishes in appearance and behaviour. Also, where different sexes are kept, courtship and breeding is so common you might see it as inevitable rather than aspirational.

DRAGONETS 6Scientific name: Synchiropus spp

6Distribution: Tropical Indo-Pacific

6Price Range: £25-55 each

6System Size: 50 or so litres can house a pair of smaller dragonet species — S. sycorax for example. Larger species will benefit from more space and the maintenance of excellent water quality will greatly increase the chances of spawning.

This inclusion is perhaps a controversial one and is included to illustrate that a species-specific aquarium does not have to be the reserve of animals that are impossible to keep with other tank-mates. Dragonets such as Mandarins, S. splendidus and S. picturatus, and Scooters (including the beautiful ruby red species, Synchiropus

sycorax), are frequently stocked into mixed reef aquaria with varying degrees of success. They are slow, methodical pickers at tiny benthic invertebrates and although the best individuals will accept frozen offerings, they present a number of challenges to aquarists — even those prepared to add live copepods and similar to their aquaria on a regular basis.

With some experience of marine aquaria Synchiropus species can be maintained in tanks less than 125-litres capacity with adequate rockwork for them to forage over; mature live rock can work well here and often provides starter colonies of the amphipods, isopods and copepods that these fish love to eat. The main reason for considering them for the species-specific system is to reduce competition.

When feeding is relatively easy then keeping more than one individual also becomes easier and the aquarist can consider stocking pairs into the system. Dragonets often reward good husbandry with highly visible courtship and spawning at dusk with apparently insatiable regularity.

Anyone who encounters Garden eels — whether it be diving in the tropics or seeing them in a public aquarium — can’t fail to be taken by them. These colonial fish emerge from their burrows to feed on zooplankton, and resemble a field of candy-canes with their hockey-stick profiles. It’s only a bonus that these attractive fish with their rather glum-looking, goby-like heads often sport the most striking patterns and colours.

An aquarium for garden eels needs to be planned from the ground up. Perhaps the most important criterion is the presence of something to actually burrow into, and that means sand or fine gravel to a depth of at least 10cm. Some aquarists with experience of Garden eels advocate 30cm substrate depth, which few aquarists will have ever laid down, let alone in a reef aquarium. Once a burrow is formed its resident is unlikely to leave and specimens will deteriorate rapidly if not offered something to dig in to.

Substrate alone doesn’t guarantee success. Garden eels are difficult to feed (they’ll only take food in suspension, and then often only when it’s live) and if they’ve not been housed well since importation they may be emaciated — quality, increased rations will be necessary to replace their missing body mass. Settled individuals will accept most meaty diets including frozen copepods, brine shrimp and smaller mysids, which are ideally offered a few times per day in small amounts to prevent over-polluting the tank.