How To Set Up An Aquarium For A Seahorse

These lovely and strange life forms are very endearing and become a household pet very easily. Children in particular seem to be fascinated by them.

The care of seahorses is not to be undertaken lightly. They need very similar maintenance to a fish only marine system, so the requirement to carry out maintenance regularly needs to be accepted.

Seawater will need to be mixed and the preferred pH range is 8.0 to 8.3 and SG (specific gravity) is 1.021 to 1.024. Temperature should be in the range 75 to 78 deg F (obviously this is for tropical species). As with all system types the seawater quality needs to be high – the ammonia and nitrite readings need to be nil, and nitrate should be 10 ppm (parts per million) or less. It is also necessary to carry out regular routine seawater changes, the guideline amount being 10% of the net aquarium gallonage as with other system types.

Unlike the fish only and reef systems, seawater movement should not be vigorous. There should be movement though and this can be created by powerheads in the normal way. They will of course have lower outputs. To judge the power of the current consider a field of corn. In a gentle breeze the corn will stir and sway a little but will be nowhere near thrashing about. The requirement for low strength currents is because the seahorse is not a strong swimmer.

Again as with all aquarium systems, seahorses need a bio-filter for their well being. This could be live rock, or a canister filter will suffice. If live rock is used it is best to try and ensure there aren’t any sharp edges that the seahorses could damage themselves on. Whichever type of bio-filtration is selected, it must be mature. Seahorses cannot be introduced until there is a mature bio-filter.

Unlike say surgeon fishes, seahorses do not demand a lot of space, they move about calmly and serenely. They should not be crowded of course. This means that the aquarium need not be large. For example, a 3ft by 1.5ft by 1.5ft aquarium would not be overcrowded with five seahorses (remembering that some are small and some much larger).

Decorating the aquarium is straightforward. There isn’t any need for a reef structure, but a few rocks (without damaging edges) could be used. These, as said, could be live rock, sufficient to ensure good bio-filtration. A decorative sand bed could also be used if desired, but it must be remembered that the bed needs to be cleaned periodically if necessary to ensure it is healthy. Sand traps detritus and could become dirty fairly quickly.

Lighting the aquarium does not present any problems as, like fish, the seahorses simply need to see and be seen. Generally, two fluorescent tubes should suffice, and a ‘dawn/dusk’ cycle could be introduced by using an electric timer. This will move the system a little closer to the natural sequence, as livestock should not be plunged into darkness or suddenly bathed in light. If algae are to be used (see below) then the lighting should take account of this.

Seahorses use their tails to hold themselves in any particular place, so it is necessary to provide them with anchor points. Some aquarists use artificial plants which can be anchored down, ensuring that the plants are constructed of soft plastic. Others use real plants and this is better. In this case ‘plants’ means the machro algae Caulerpa. This alga is decorative and reasonably easy to grow, some types being easier than others. It should sway in the seawater currents and when there is plenty of it looks very attractive. The alga has another purpose too, as when established it requires nutrients and these include phosphate and nitrate, two that the aquarist doesn’t desire. Caulerpa can grow vigorously and it should be harvested from time to time, always leaving enough for the seahorses and to ensure the algae stock continues to grow.

Feeding seahorses could be a problem as they are sometimes finicky and ignore the aquarist’s usual offerings of dead material. Flake food is a waste of time, the usual food being brine shrimp and mysis shrimp. If the seahorses refuse the de-frosted varieties then they will need to be started on live brine shrimp. These can sometimes be purchased from the local fish shop (LFS) or the aquarist can rear them himself. There are rearing kits available that provide all that is required and it is not a difficult job by any means.

Seahorses will take de-frosted shrimp often, however, and if this is the case it is best to use ‘enriched’ varieties as well as more than one type. Rather than putting a great deal of food in the aquarium, which will put pressure on the seawater quality, the aquarist could target feed, dropping food close to the seahorse’s current location. The low seawater circulation will not hinder this practice too much.

The fact that seahorses are being kept and there is low seawater circulation does not mean that nothing else can be kept in the aquarium. The aquarist could keep pipefish that also require the same environment. In addition there are snails and various other life forms that will not be detrimental.

If the aquarist sets the aquarium up with care, and provides a stable and high quality environment, then he or she should have an aquarium that will provide many hours of fascination. It is likely that children will want to be involved which is good. It could even be that the aquarist is presented with new additions to the aquarium in the form of many baby seahorses, born unusually from the father.

I have noted below a website from where an interested aquarist can extract much additional information.

  1. Good article, John. I’ve been thinking of setting up something like this for the grandkids.

  2. Thanks for the kind words Rick.
    If you do decide to go ahead I bet the grandchildren will be fascinated. You’ll be the one doing the essential maintenance though!

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