Re:New SH Tank questions

Pete Giwojna

Dear Bentley:

I like your choice of a 47-gallon column tank for your seahorse setup — it has the superior height that is so important for seahorses as well as sufficient water volume to provide excellent stability and a comfortable margin for error. With the 47-gallon column tank and a protein skimmer, you have a good start towards an excellent seahorse system.

First and foremost, you will need to install a biofilter of some sort. This can either be an external filter of some sort with biofiltration media, perhaps an undergravel filter within the tank itself, or sufficient live rock to provide adequate biological filtration (nitrification and denitrification). Depending on what sort of biofiltration you use, you may also need one or more small powerhead for additional water circulation to eliminate dead spots. Most home hobbyists find that a heater is useful to maintain the tank from dropping below the minimum temperature during the winter, depending a part of the country they live in…

You will also need to provide some convenient perches or hitching posts for your ponies, Bentley. Suitable hitching posts for your seahorses can consist of lifelike artificial corals and realistic synthetic plants designed for use in saltwater aquariums, or colorful living macroalgae and seahorse-safe soft corals, or any combination thereof. If you read the pinned topic on artificial corals and hitching posts at the top of this forum, it covers many of the most popular synthetic decorations for seahorses, complete with photographs. If you decide to try an assortment of colorful artificial corals, seahorses often prefer red or orange pieces, and bright yellow, pink and purple corals are also popular. Many hobbyists report good results using artificial tree sponges, gorgonians and sea rods, staghorn coral, artificial Acropora corals, octopus coral and pillar coral in the appropriate colors to keep their seahorses looking their brightest. They look entirely natural and lifelike, with lots of branching projections that make great hitching posts for seahorses. Oh, and the cup coral often makes a great ready-made feeding station! Nature’s Image, Living Color, and Rock and Waterscape are the three best sources for artificial corals, in my opinion, with the Signature Coral Corporation also producing some useful pieces.

When it comes to colorful macroalgae, this is what I usually advise home hobbyists, Bentley:

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Macroalgae — Living Hitching Posts

For live hitching posts, I prefer decorative marine plants or macroalgae in a variety of shapes and colors and color — reds, golds, and yellows in addition to green varieties, some tall and feather, some short and bushy — to provide them with natural hitching posts and shelter. I like to start with a mixture of red and gold Gracilaria (Ogo), which grow well attached to rocks, and artfully arrange them around a lush bed of assorted bright green Caulerpa, which thrives in a sandy substrate. Any of the plumed (feathery) or long-bladed Caulerpa would be ideal for this, such as Caulerpa sertularioides, C. mexicana, C. ashmedii, C. serrulata or C. prolifera. But they may not be the best choice for tall tanks since none of these species will grow more than about 4-6 inches in height at the most.

Be sure to thin out the fast-growing Caulerpa regularly; when you remove the excess strands and fronds, you’re exporting phosphates, nitrates and other nutrients from the tank, thereby helping to maintain good water quality, and thinning out the runners helps keep it from going sexual.

When thinning out Caulerpa and other macroalgae, take care not to actually cut it. Remember, you’re not pruning hedges or trimming trees — the idea is to carefully pull up and remove continuous, unbroken fronds or entire runners with numerous old fronds. Simply thin out the colony of excess strands, gently plucking up convenient fronds that can be readily removed intact.

Typically, the Caulerpa colony will put out horizontal runners or strands (i.e., the stolon of the plant) and a number of vertical leafy structures or "fronds" will sprout upwards from these runners. When I am thinning out a bed of Caulerpa, I try to weed out the older growth and pluck out whole runners complete with several feathery fronds so that I minimize any breakage when I remove the older plant material from the colony. In other words, rather than plucking off individual fronds at the attachment where they sprout from the runners, I prefer to extract an entire runner or strand together with all of its fronds, which allows me to remove more plant mass with as little breakage or damage to the entire colony is possible. Often there will be older strands and fronds that have separated from the rest of the colony naturally, and these are the best runners to target since there will be little or no breakage when they are removed. By regularly removing the older runners and the associated fronds, you can interrupt the life cycle of the Caulerpa and prevent it from going sexual. This is best done on a weekly basis to be safe, if the Caulerpa colony is growing rapidly.

A little breakage when thinning out the Caulerpa is fine, but cutting or breaking too many strands will result in leaching undesirable substances into the aquarium water as the Caulerpa’s lifeblood drains away. Too much cutting or breaking can thus sap the colony’s strength and cause die offs or trigger the dreaded vegetative events that judiciously thinning out the colony otherwise prevents.

The Caulerpa colony also dies off en masse after reproducing sexually, and the massive die off of Caulerpa for any reason can present a danger to the aquarium. There are undesirable substances leached back into the aquarium from the dying colony, and the resulting decay of a large quantity of organic matter all at once may trigger a bacterial bloom and subsequent drop in the dissolved oxygen level of the aquarium. The combination of these events can sometimes result in the loss of specimens or even crash the entire system.

Such a "vegetative event" is unmistakable because it will often turn the water in a small, close system aquarium milky white until the filtration begins to have an affect. If such an event occurs, the observant aquarist can often save the day by performing a series of water changes and employing activated carbon and other chemical filtration media to remove the harmful substances that have been released.

If you find it difficult to obtain Caulerpa (it’s illegal in some coastal areas) or you’re simply concerned about your ability to maintain and control of Caulerpa properly, just use a different forms of macroalgae that grows less rapidly instead and you can get the same sort of benefits at relatively little risk. In that case, some of the other macroalge you may wish to consider are Gracilaria, Ulva, Codium, Chaetomorpha, and Chlorodesmis. Hawaiian Ogo (Gracilaria sp.) are bushy red-to-brown macros that do well under low light levels. Sea Lettuce (Ulva sp.) are deep green sheets of algae that do best under a little stronger lighting. Maiden’s Hair (Chlorodesmis sp.) are bright green tufts or clumps of very fine-bladed algal mats to grow attached to small rocks. Codium is another bright green algae with an attractive branching structure. All of these types of macroalgae are much less prolific and slower growing than Caulerpa. However, like all macroalgae, they should still be harvested periodically in order to export the excess nutrients they have consumed.

Aside from red and brown Gracilaria and the bright green Ulva and Maiden’s Hair, some seahorse keepers also like the Chaetomorpha turf algae or spaghetti algae, as it is also known. It can best be described as looking like the clumps of the colorful plastic grass we use to fill Easter baskets. Good on seven It is popular because it is slow growing and doesn’t require the kind of pruning that Caulerpa needs, and because it comes loaded with microfauna: miniature feather dusters, copepods and amphipods, tiny snails and micro stars. In short, Chaetomorpha is another interesting marine plant that can add some extra variety to a lush bed of macroalgae.

If you are looking for colorful macroalgae that goes well with live rock and will provide good hitching posts for seahorses, then I think you might like the "red-on-rock" algae species offered by Inland Aquatics. They are more colorful and won’t overgrow or overwhelm your tank.

Other colorful red macroalgae that are well worth trying include Heymenia or Halymenia (commonly known as dragon’s tongue) and Botryocladia red grape algae, which is commonly known as red grape Caulerpa (even though it’s not a species of Caulerpa at all) The dragon’s tongue is a very attractive red species that either likes the conditions in your aquarium and thrives, or doesn’t like the tank conditions and disappears. When it thrives, it’s a beautiful red macroalgae that’s an asset to any aquarium. The distinctive appearance of these Botryocladia and it’s reddish coloration make it an aquarium favorite which is also useful since a large colony makes a good natural feeding station for seahorses. It does well when attached to the rockwork.

Maiden’s hair algae and sea lettuce (Ulva spp.) are bright green species of macroalgae that normally grow attached to rocks and are typically sold that way for aquarium use. They could also be placed amid your live rock where they would receive bright light.

If you are looking for marine plants to maintain in a sandy area of your tank, many species of Caulerpa, Merman’s shaving brushes (Penicillus spp), Udotea "sea fans," and Halimeda sea cactus are available, all of which are just anchored in the sandy bottom and will put out rhizoids or holdfasts to keep himself in place. Other species of Halimeda are available that sprout from live rock instead, so that’s another option if you prefer.

But the Halimeda sea cactus, Penicillus shaving brushes, and Udotea sea fans are all calcareous macros that require high levels of calcium in order to thrive. To maintain them successfully, you will need to monitor the calcium levels, total alkalinity, and carbonate hardness of your seahorse setup, provide occasional supplements of calcium or Kalkwasser, and maintain the aquarium more like a reef tank than an ordinary saltwater system.

Codium is another green macroalgae that’s very attractive in the aquarium and very distinctive in appearance (with its branching structure, it looks more like some sort of green gorgonian or bushy seafan, rather than a species of algae). It can grow several inches tall and may develop a bushy branching crown several inches in diameter. The Codium thus makes a good natural hitching posts for seahorses (Peggy Hill, pers. com.) and is a good choice for a well lit sandy area in the tank.

Some macroalgae are rootless and do not anchor in place. This is true of the Chaetomorpha turf algae or spaghetti algae, for instance. It grows in tangled clumps that look like nothing more than the colorful green Easter grass we use in our Easter baskets as betting for the jellybeans, marshmallow chicks, and chocolate bunnies. Chaetomorpha is therefore not very aesthetic looking in your main tank, but you can’t beat it for use in refugia or algal filters because hordes of copepods, amphipods, and other microfauna love to shelter, feed, and breed in the tangled masses of the spaghetti algae.

Like the Chaetomorpha, different types of Gracilaria or Ogo are often cultured by tumbling them so that they are always in motion, exposing different areas of the plant masses to the sunlight and assuring that clean water circulates through them continually. Several different types of Gracilaria (red, brown, green) are available and are typically sold in clumps by the bag or the pound. They don’t have roots as such, of course, but if you wedge them in crevices in your live rock or anchor them in place with a small rock or piece of coral rubble, they will attach to a hard substrate and grow well under favorable circumstances. Again, like the Chaetomorpha, these balls or clumps of Gracilaria/Ogo are ideal for culturing copepods and amphipods in your sump or refugium, but they will also look nice in your main tank once they take hold.

When it comes to the live macroalgae (living marine plants), you can get various species of Ogo (Gracilaria) from Ocean Rider, but for more color and variety, there are a number of other places to order suitable live plants online.

For example, Inland Aquatics has perhaps the best selection and variety of macroalgae available:

Aquacon is another good source for cultured macroalgae:

Click here: Marine Plants for Saltwater aquariums

Other good sources for macroalgae include and


Seahorses also like live rock, particularly colorful pieces that are heavily overgrown with pinkish or purplish coralline algae. Aside from looking pretty, live rock also provides additional biological filtration (both nitrification and denitrification) for the aquarium and provides shelter and sight barriers that make the seahorses feel secure.

In short, special attention to the hitching posts you select when decorating your seahorse tank. Strive for bright reds, oranges, and yellows in anything your seahorses may adopt as a holdfast. These aquatic equines — especially the stallions — will often choose one particular hitching post as their home base and spend much of there time perched right there (think of your Dad hunkered down in his favorite easy chair in the den). Once they adopt a favorite base of operations like this, they will often proceed to change coloration to match their preferred resting spot. So you want to encourage them to adopt one of the more vivid pieces as a favorite holdfast whenever possible.
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Okay, Bentley, that’s the quick rundown on macroalgae and other hitching posts for a seahorse setup.

For additional tips on setting up your 47-gallon column tank, I would strongly urge you to participate in the Ocean Rider seahorse training program. It is a correspondence course conducted entirely via e-mail that is completely free of charge and discusses everything you need to know about setting up a new seahorse tank and optimizing it for seahorses, as well as comprehensive information on the care and keeping of seahorses, including feeding, compatible tank mates, courtship and breeding, raising the babies, and disease prevention and control. (For complete details on the seahorse training program, see the pinned discussion thread at the top of this forum.)

The first lesson in the training course is devoted entirely to selecting a suitable tank (which you have already accomplished) and preparing it to create ideal conditions for seahorses. It includes a list of all of the equipment and items you’ll need for your seahorse setup and discusses hitching posts and aquascaping in depth. Likewise, the second lesson is devoted entirely to cycling a new seahorse setup and establishing the biological filtration. There are a total of 10 lessons, all of which are loaded with useful tips and helpful suggestions for the seahorse keeper. In short, the training program discusses setting up for seahorses and maintaining your seahorses in much more detail then we can go into on a simple discussion forum like this.

If you would like to give the seahorse training program a try, Bentley, just contact me off list ([email protected]) with a brief message that includes your full name (first and last) and I will get you started out with the first lesson right away. Once we begin corresponding, I will continue to work with you personally until your new aquarium is up and running, ready to receive the seahorses.

Best of luck with your new seahorse tank!

Happy Trails!
Pete Giwojna

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