Sea Grasses

Dear Poor2today:

Many seahorses are indeed right at home in seagrasses such as turtle grass (Thalassia testudinium), shoal grass (Halodule wrightii), eelgrass (Zostera marina) or manatee grass (Syringodium filiforme). But I generally do not recommend starting out with a seagrass system for your first seahorse tank. Seagrasses are rooted plants that require a deep substrate with the proper grain size and consistency. They need relatively bright lights and can be tricky to establish in the aquarium. Seagrass tanks are best viewed from above, rather than the side, and it may be difficult to view your seahorses (or feed them) in such a setup. Plus they have a few other drawbacks hobbyists should consider. Here is a discussion of seagrass setups from my new book (Complete Guide to the Greater Seahorses in the Aquarium, unpublished) that will give some pointers on how to proceed if you decide to go ahead with a seagrass biotype, and which also discusses the potential drawbacks of such a system:

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The Seagrass System/Mangrove Tank.

Another interesting option for seahorses is to establish an aquarium that duplicates a habitat consisting primarily of seagrass and mangroves. This would recreate a biotype where several seahorse species are naturally found, including Hippocampus zosterae, H. erectus, H. reidi, H. kuda, and H. histrix (Delbeek, Nov. 2001). Charles Delbeek is one very prominent aquarist who maintains a seagrass/mangrove setup, and the following information is based largely on his system and recommendations.

Over the last 5-10 years there has been an explosion of interest in seagrass and mangroves as aquarium specimens, creating a demand and a growing market for these. For instance, mangrove seedpods with sprouting leaves are now readily available to the home hobbyist and seagrass is becoming more so with every passing year. Seeds and/or seedlings for Thalassia turtle grass and Enhalus tape seagrass should soon be available to hobbyists in abundance (Delbeek, Nov. 2001).

Delbeek recommends a shallow, broad tank such as a standard 40-gallon breeder for a seagrass and/or mangrove setup, which will allow a large surface area to grow the seagrass and still leave plenty of room for positioning mangrove seedpods along the perimeter or perhaps as a centerpiece. For the substrate, he suggests at least four inches of a calcareous sand/gravel mixture with a variety of grain sizes, ranging from one or two millimeters to a centimeter or so in diameter (Delbeek, Nov. 2001). If possible, live sand is preferable for this. It is a good idea to build up the sand bed where the mangrove seedpods will be placed, since they will benefit from a deeper layer of sand that allows better root development (Delbeek, Nov. 2001).

Certain corals occur naturally in mangrove/seagrass areas, and Delbeek suggests adding a variety of these to your design as fragments attached to a few small pieces of live rock artfully arranged on the bottom. To complete the biotype, he recommends including small fragments of Acropora spp., Montipora digitata, Pocilliopora damicornis, Porites cylindrica or Seriatopora hystrix. Free-living corals such as Fungia, Herpolitha, Polyphyllia or Trachyphyllia are also good choices that would not look out of place in a seagrass/mangrove system (Delbeek, Nov. 2001).

Filtration for such a setup can be very simple since the deep live sand bed and plants provide the biological filtration and denitrification ability. Delbeek suggests using a canister filter for light mechanical and chemical filtration, supplemented by a protein skimmer to deal with excess nutrients created by the feeding sea horses. Gentle to moderate currents can be directed as needed by the use of small powerheads and/or the canister filter returns.

Since a seagrass/mangrove tank is best viewed from above, and not just the front, he recommends using a hanging light fixture that will allow the tank to be observed from the top as well, with the tank itself placed on low stand. For best results, the lighting fixtures should include a combination of metal halide and fluorescent lights (Delbeek, Nov. 2001). In addition, placing the tank in a location where it will receive a few hours a day of direct sunlight is also very desirable, as long as overheating of the aquarium water does not become a problem.

Delbeek recommends allowing the sand bed to mature and the seagrass to begin to grow and spread for at least six months adding any seahorses. This break-in period will also allow time for the mangrove seedpods to take root and begin to grow and establish themselves, as well as building up a heavy population of microfauna in the sand bed and seagrass (Delbeek, Nov. 2001). Once the seahorses are introduced, they will enjoy grazing between meals on the abundant copepods and amphipods that have established self-sustaining populations in the tank.

Once the seagrass is established, it will grow rapidly. As they reach the surface, they will grow along the top just beneath the water, thus creating shady retreats for your seahorses underneath the overhanging mat of vegetation (Delbeek, Nov. 2001). Although the seahorses will enjoy the dim light under the canopy of seagrass, the corals you’ve carefully added will not, so make sure your coral fragments are positioned in well-lit areas.

A well-designed seagrass system that includes mangroves and a variety of carefully selected corals makes a very interesting exhibit. It creates a veritable Garden of Eden for seahorses, which feel right at home in the natural surroundings. The lush seagrass and mangroves provide them with abundant shelter and privacy, and the seahorses enjoy hunting the microcrustaceans that thrive in such setups.

But there are a few drawbacks to such system. In the first place, it can sometimes be difficult to obtain seagrass and mangrove seedpods. Once obtained, it can be tricky to get the mangroves and seagrass off to a good start. Once started, it takes a long time to establish a seagrass/mangrove system and for the live sand bed to mature before they’re ready for seahorses. Once the tank is ready and the seahorses have been introduced, such systems are not always the best setups for observing seahorses and studying their complex behaviors. Seagrasses do best in shallow setups whereas seahorses do best in taller (deeper) tanks. Finally, brightly colored seahorses may not retain their vivid coloration amidst all the greenery. For instance, bright orange or red seahorses would stick out like a sore thumb in a bed of seagrass, and when they feel too conspicuous, seahorses are apt to revert to cryptic coloration.

In short, a seagrass/mangrove biotype is a wonderful choice for experienced hobbyists who want to maintain seahorses in a natural setting, but it may not be the best choice for beginners and less advanced aquarists. If you don’t have a green thumb or a lot of seahorse savvy, you may be better off starting out with a standard SHOWLR tank instead. <Close quote>

That’s the quick rundown on seagrass systems, Poor2day. If you feel you would still like to try the a seagrass habitat, which can be a spectacular setup once the plants are well-established, I will be happy to give you some pointers to help you get started off on the right foot. For example, turtlegrass (Thalassia testudinium) will require a rich sand bed, well matured, of at least six-inches deep and strong lighting (at least 5 W per gallon), which will probably require you to upgrade to metal halide lighting. Metal halides will in turn increase the potential for overheating, and it’s very important to avoid heat stress when keeping seahorses. Manatee grass will require at least a four-inch deep sand bed, well-established, and can grow to over 2 feet tall. The shoal grass is much shorter and only requires a mature sand bed about 3 inches deep in order to thrive.

Here’s a discussion from Eric Borneman on reef.org (posted to reef-l emailing list, Sunday the 20th of June 1999) regarding the proper substrate for Thalassia and how best to plant it:

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I am going to be breaking down my 45 gallon lagoonal reef in a couple of months and setting up a multi-tank system including a Turtle/Eel Grass tank as a refugium, etc. Any words of wisdom?

Yes indeed-ee!

I will give you tips based on my experience and some based on the Texas Guide to Planting Seagrasses.

Make sure the sediments are fine and silty and rich in organics prior to planting. I used a 1/4 to 1/2 tablet of a freshwater plant fertilizer called Hilena Crypto, by Tetra, to help the roots establish…seemed to help, but I have never re-dosed/fertilized. Once every month or so for about the past six months, I have shut off flow to the seagrass tank for a day or two, and added an iron supplement to the water. I didn’t appear to require it, but several studies I had showed a propensity for iron limitation in seagrasses – Thallasia and Zostera. So, I did it for the heck of it. I don’t remove the dead leaves.

My sediments are 6-8" deep in that tank, although if you plant them to the bottom of the tank, I am not sure they have to be quite that deep, although I would personally love to see 12" if the tank could accomodate it.

Lots of important commensal (?) bacteria and nitrogen fixers hanging out near the rhizomes of Thallasia, theorized to provide nitrogen and other material to roots. Therefore, keeping some sediments around this area is probably a nice plan. The sediments are so mucky, it sort of just clumps together anyway, although a couple of places apparently ship bare root. Texas Guide says this is very bad for them, especially air exposure, and I would concur as I lost a lot of plugs from ones I received bareroot, and almost none of the ones I collected myself. Plus, the fauna in that sediment is so prolific its hard to not get excited about the carbonate mud. Wish I could add a scoop or two of this to the tank on a regualr basis.

I do 2 x 175 watt 6550K and two 48" grow lights (Home Depot Chroma 50’s if I recall?) above the tank…corals present seem to like it fine, and they thrive on the creatures in this area, too. I have quite low flow in this tank, and do get occasional patchy cyano which I leave I know its doing just what it should be doing in this area, and it never spreads to other tanks in line.

I’ll bet like other plants there is probably a proper time of the year to do transplanting, but I’ll be derned if there’s a marine farmer’s almanac. I would imagine prior to the fastest growing season, but who knows? <Close quote>

You should also check out Anthony Calfo’s excellent online article titled "Beautiful Seagrasses — Keeping True Flowering Plants in Your Marine Aquarium." If you copied the following URL and paste it into your web browser, it will take you directly to the article:

http://www.reefland.com/rho/0305/main3.php

And be sure to read through these FAQs on true marine plants in seagrasses at Bob Fenner’s wet web media site, which contains a lot of good information on the subject including some possible sources for the seagrass:

http://www.wetwebmedia.com/marvascpltfaqs.htm

When it comes to obtaining the seagrass, Thalassia turtle grass is available Inland Aquatics at the following URL:

http://www.inlandaquatics.com

Mangrove seedlings are often available from Aquacon at the following website:

Click here: Marine Plants for Saltwater aquariums
http://www.aquacon.com/vip.html

Florida Pets used to be an excellent source for Thalassia and other types of seagrasses, but I haven’t heard from them for a while now and I’m not sure if that’s still the case:

http://www.floridapets.com/

If you have difficulty obtaining the live seagrass that you’re interested in, Poor2day, an excellent alternative would be to use lifelike artificial seagrass for your seahorse tank instead. Bio Models (<http://users.adelphia.net/~biomodels/&gt;) is by far the best place to get artificial marine plant replicas, and that’s the outfit all of the public aquariums and zoos used for that purpose. They can provide you with extremely realistic synthetic turtlegrass, eel grass, etc., and neither your eyes nor the seahorses will ever be able to tell the difference between the fake stuff provided by Bio Models and the real thing. That would eliminate many of the potential obstacles and complications you will be facing in establishing a seagrass biotype, such as the high-intensity lighting and problem with overheating, need for a deep live sand bed, and lack of availability.

Personally, 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) and artfully arrange them around a lush bed of assorted bright green Caulerpa. 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 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. Simply thin out the colony of excess strands, gently plucking up convenient fronds that can be readily removed intact. A little breakage 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.

If 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, 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. 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.

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 on mid-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.

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.

Best of luck with the seagrass biotype you are planning for your seahorses, Poor2today! Here’s hoping it turns out to be every bit as beautiful and unique as you have envisioned.

Respectfully,
Pete Giwojna