Re:New here!

Pete Giwojna

Dear Carrie:

Welcome to the group!

Cycling your new aquarium without the use of live fish is an excellent idea. It generally takes around 3-6 weeks to cycle a new aquarium from scratch, so your set up should be progressing nicely.

But I would rethink those first additions to the aquarium you were contemplating, Carrie. I would avoid the sand sifting starfish at least for now. Echinoderms (starfish and sea urchins) are very sensitive to water quality and should be reserved for mature, well-established aquariums rather than new tanks that have just finished cycling. In addition, sand sifting starfish are often counterproductive in my experience, since they tend to prey on the beneficial microfauna that inhabits live sand. In a standard seahorse setup, I would stay away from sand sifting starfish and you will be better off if you don’t attempt to keep any sea stars in your tank until it stabilizes and reaches a state of equilibrium (i.e., not for several months yet).

The same holds true for delicate cleaner shrimp, Carrie. Decorative cleaner shrimp are a wonderful asset for your cleanup crew but they do best in a mature, well-established aquarium. So for best results, I would hold of on adding the cleaner shrimp to your cleanup crew until you’re new aquarium has been fully cycled and up and running for a few months.

When it comes to sanitation engineers, I prefer a cleanup crew consisting of a mixture of assorted snails and micro hermits (heavy on the snails but light on hermits) at a density of up to 1-2 janitors per gallon. The snail assortment may include bumble bee snails, trocha snails, margaritas, Astrea and Cerith snails, red foot Moon snails, etc., but especially Nassarius snails.

Nassarius snails are terrific detritivores and amazingly active for snails. They’ll bury themselves until they detect the scent of something edible, and then erupt from the sand and charge out to clean it up.

A varied assortment of snails is very desirable because different types of snails have different habits, seek out various microhabitats within the aquarium, and prefer to eat different things. Some are herbivores that feed on microalgae, and some of the herbivorous snails prefer to graze on it from the substrate, others like to to clean it from the rocks, and still others love to scrape algae off the aquarium glass. Furthermore, the different herbivorous snails tend to specialize on different types of microalgae and have definite preferences as to the types of algae they will eat, so it’s important to have a nice variety of snails that cover all the bases in that regard. It’s equally important to include some omnivorous snails in your assortment, which will go after meaty leftovers, along with the vegetarians. And you’ll want to have plenty of detritivores, too, which will feed on detritus and decaying organic matter in the aquarium

For best results, Astrea sp. snails should go in the tank as soon as the ammonia and nitrite levels are down to zero in order to keep nuisance algae from gaining a foothold in your tank. Introduced as soon as possible to a new aquarium, that has reached this cycling phase, Astrea snails effectively limit the development of all microalgae. In other words, they are good at eating diatoms, but will consume red slime and green algae as well.

But you must avoid predatory snails such as tulip snails, horse conchs, crown snails (Melanogena corona), and the venomous cone snails (Conus spp.), which can kill a human with a single stain from their harpoon like radula. Tulip snails, horse conchs, and crown conchs will hunt down and eat the other snails in your cleanup crew, whereas cone snails prey on small fishes in addition to presenting a deadly hazard to the aquarist.

For hermits, I like a combination of Dwarf Blue-leg (Clibanarius tricolor), Left-handed (Calcinus laevimanus), Mexican Red Legged Hermits (Clibanarius digueti) and above all, Scarlet Reef hermit crabs (Paguristes cadenati), which are my personal favorites.

The Scarlet Reef Hermit Crab (Paguristes cadenati) is a colorful micro-hermit that’s a harmless herbivore. So cannibalism isn’t a concern at all for these fellows, nor are they likely to develop a taste for escargot. As hermits go, most of the time the Scarlet Reefs are perfect little gentleman and attractive to boot. I even use them in my dwarf seahorse tanks. Best of all, they eat all kinds of algae, including nuisance algae such as red, green and brown slimes, as well as green hair algae.

Stick with hermits like the above, which are known as micro hermits because they start out tiny and stay small. Avoid Anomura species of hermit crabs no matter how small they are, however, because they will kill Astraea snails to obtain their shells.

A mixture of the snails and micro hermits we have discussed will provide a very good balance of herbivores, omnivores, and detritivores that are all active scavengers and completely compatible with seahorses. They will clean up meatier leftovers such as frozen Mysis as well as helping to control nuisance algae.

After the tank has been up and running for several months, you can add a few large Peppermint Shrimp (Lysmata wurdemanni) and/or Scarlet Cleaner Shrimp or Skunk Cleaner Shrimp (Lysmata amboinensis) to complete your cleanup crew and add a touch of color and activity to the tank.

Peppermint shrimp (Lysmata wurdemanni) are a favorite with seahorse keepers because they eat Aiptasia rock anemones, and both the peppermints and Scarlet cleaner shrimp (Lysmata amboinensis) will perform another useful service by grooming the seahorses and cleaning them of ectoparasites. As an added bonus, they reproduce regularly in the aquarium, producing swarms of larval nauplii that the seahorses love to eat.

Just remember, it is important to select the largest possible cleaner shrimp for your seahorse tank(s). Seahorses will actively hunt small cleaner shrimp and they are quite capable of killing shrimp that are far too big to swallow whole, so the cleaners need to be large enough that they are not regarded as potential prey.

Another thing to keep in mind when introducing cleaner shrimp to your aquarium is that they are more sensitive to water quality and rapid changes in pH, temperature, or salinity than fishes are, meaning the shrimp need to be acclimated more carefully and gradually. Whereas drip acclimation should be avoided for seahorses that have been on the shipping bag for 24 hours or more, it is the perfect way to acclimate delicate shrimp from your LFS. They will do best it drip acclimated to the new aquarium over a period of several hours to allow them to adjust to any differences in the water parameters very gradually.

Shrimp that are introduced to a new aquarium too abruptly will not flourish and are liable to die within a day or two from the stress of acclimation, unable to adjust to any significant differences in pH or salinity, or they simply fail to thrive and expire a week or two later for no apparent reason. If the shock is too great, they will autotomize, dropping legs, claws and/or antennae immediately upon being introduced to the new aquarium conditions.

Mandarin Dragonets are gorgeous little fishes and make great tankmates for seahorses in the right type of setup. But in the case of mandarins, that means a large, well-established aquarium of at least 100 gallons loaded with live rock that’s teeming with copepods and amphipods. The mandarins need to have continuous opportunities to graze on suitable live foods or they generally slowly waste away and starve to death, as Leslie pointed out. In the right system, they can thrive, and will often learn to take small pieces of frozen Mysis, but your particular seahorse tank may not be adequate for Mandarin gobies. However, if you have kept mandarins before and are well aware of the risks, then feel free to try one at your own discretion, but I would wait for the tank to mature and stabilize before you did so.

The sea cuke is an interesting idea but you need to consider them with care because they require just the right type of sand and conditions to go with the right kind of sea cucumber in order to do well and avoid disaster, as discussed below.

Holothurians or sea cucumbers are echinoderms, close relatives of the starfish and sea urchins. They have the same pentameral, or 5-sided, radial symmetry as sea stars and sea urchins, which is most evident as the five rows of tubefeet that run longitudinally down their long, wormlike bodies. They are simple sessile animals that have no brain, heart, or eyes, breath through their anus and often entertain houseguests therein (e.g., pearlfish , commensal crabs, and parasitic snails, all of which are allowed to nibble freely on their innards) and routinely disembowel themselves in response to stress. Their mouth is located at the opposite end of their bodies from the busy (and oft crowded) anus and is surrounded by branching, sticky, mucus-coated tentacles, which can lengthen or shorten dramatically, and are used to sweep or mop up the substrate, gather up all manner of dead or decaying organic matter, and pass it into their mouths. Basically, they consume organic detritus and ingest fine-grained sands and sediments to digest off the bacteria, microalgae and diatoms that cover the surface of each sand particle.

The beneficial Aspidochirotiacea sea cucumbers that make useful aquarium janitors feed by burrowing into and ingesting the sediment, digesting what is edible from it, then excreting the rest. Cucumbers with this type of feeding technique make good sand stirrers and substrate cleaners. As they burrow through it, they continually swallow the silt and sand, extracting animal and plant remains as the sediment passes through their intestines. Dirty sediment goes in, clean sediment comes out. Their excrement is therefore clean and relatively nonpolluting. Feeding is a full-time occupation and nonstop operation for these burrowers, and they can process an incredible amount of sand through their intestinal assembly line. It is estimated that a single sea cucumber digests, filters, cleans, and expels up to 45 kilograms of seabed a year in this manner! Suffice it to say, there is no need to vacuum your sand bed if it houses burrowing sea cucumbers.

However, sea cucumbers in this feeding category can often be picky eaters, because some feed only on fine sand, while others prefer relatively course sand. Therefore, if the proper type of sediment a particular sea cucumber needs is not provided, it may not feed. If you have a gravel bottom in your tank or a bare glass bottom, rather than a substrate of fine "sugar" sand, do not consider sea cucumbers.

Sea cucumbers can be problematic aquarium specimens under certain circumstances because of their many unusual defense mechanism, which may sometimes have an adverse impact on their tankmates, as described below:

(1) Evisceration or autovisceration: they may forcibly eject all of their internal organs through their anus, presumably to distract predators while the cuke makes a slow-motion getaway. This act of voluntary disembowelment surprisingly does the sea cucumber no permanent harm, as the internal organs are regenerated over a period of months, but it gives a new meaning to the phrase "puking your guts out." Spilling their guts in this fashion is a response to a life-threatening situation — predation, chemical stress, low oxygen levels that cannot support them — and can help the sea cucumber survive until conditions are more favorable. No chemical discharge normally occurs when they eviscerate, so this odd behavior is not a threat to the aquariums inhabitants.

(2) Regurgitating Cuvierian tubules — glue traps. At the slightest provocation, some cukes expel masses of very strong, long, extremely sticky, filamentous threads (Cuvierian tubules) to deter predators. Other animals, especially spiny crabs, become hopelessly trapped in these adhesive tubules and the more they struggle, the worse they become entangled until they are as incapacitated as if they were wrapped up tightly in a straight jacket. Once trapped in this sticky web, they are doomed to a slow death. The hobbyist can intervene to save the entrapped animal(s), of course, but disentangling them by hand is a painstaking process that can be the devil’s own business.

(3) Animated Goop — morphing into tight places. Some cukes can more or less liquefy their bodies (a process that hobbyists often refer to as "goopifying") in order to ooze or pour themselves into the tighest cracks, crevices, and hidey holes for protection. Once they’ve holed up in this manner, they inflate their bodies with water and solidify their skin again, wedging themselves tightly in place to prevent their extraction. A harmless enough trick, you might think — until the tight space they wedge themselves into and plug up is the intake, drain, or overflow of their aquarium! To prevent this sort of accident, aquariums that house Holothurians should be cucumber-proofed, a task most seahorse keepers have already accomplished in order to prevent their ponies from being suck up by filter intakes and overflows.

(4) Chemical Warfare — the dreaded "cuke nuke!" Some sea cucumbers release toxins (holothurin and holotoxin) while alive when threatened (or even after death, in some cases). These toxins can be quite deadly to fishes but don’t seem to affect most invertebrates. The group of colorful sea cucumbers known as Poison Apples are the worst offenders in that regard, and a large specimen is said to be able to release enough toxin to kill all of the fishes in a small, closed system aquarium and wipe out the entire tank. Such rare Holothurian-related aquarium accidents have become known as "cuke nukes," an unfortunate appellation that has given all sea cucumbers a bad reputation with hobbyists.

This is regrettable because the beneficial Aspidochirotiacea burrowing and deposit-feeding sea cucumbers are such good sanitation engineers and are much less likely to find themselves in a situation where they must call their defense mechanisms into play, and far less likely to cause ANY trouble than their toxic cousins, the Poison Apples. Still, any aquarist who is considering adding sea cucumbers to his tank should be aware of the potential risks. Anyone who is contemplating cukes should read Rob Toonen’s excellent series of articles about them, which outlines the benefits and risks they may pose in greater detail. It is available online at the following URL:

Click here: Aquarium Invertebrates

Sea cucumbers aren’t for everyone, but the right kind can be useful sand shifters and detritivores for seahorse keepers that deep live sand beds (DLSBs) or run modified reef tanks. If you want to give sea cucumbers a try, avoid the colorful filter-feeding Poison Apples, stick with the burrowing sand movers, don’t overstock (one or two cukes is usually plenty), and handle them with care. (The recommended stocking density is no more than 3 inches of sea cucumber per 20 gallons.) If you have any doubts about your ability to handle or care for sea cucumbers properly, then you will probably be better off sticking with snails (especially burrowing Nassarius snails), microhermits, and cleaner shrimp (later on, after the tank matures) as your sanitation engineers.

There have been a few other threads on the Ocean Rider Club discussion board at from hobbyists who were just starting out with seahorses that you should also find to be of interest, Carrie. They discuss setting up an ideal system for seahorses, filtration, feeding, lighting, circulation and so on. I’ve provided links to those discussions for you below, so please check them out when you have a chance, Carrie, if you haven’t already seen them. I think they will answer many of your questions about keeping seahorses:

Click here: – Seahorse, Sea Life, Marine Life, Aquafarm Sales, Feeds and Accessories – Re:ok stocking density…,com_simpleboard/Itemid,144/func,view/catid,2/id,1526/#1526

Re:Hello, newbie here! – O,com_simpleboard/Itemid,144/func,view/id,1004/catid,2/

Click here: – Seahorse, Sea Life, Marine Life, Aquafarm Sales, Feeds and Accessories – Re:Setting up a 100gal for,com_simpleboard/Itemid,144/func,view/id,1382/catid,2/

Re: Guidance on Keeping Seahorses:,com_simpleboard/Itemid,144/func,view/id,639/catid,2/

Re: New to seahorses and I have lots of questions!,com_simpleboard/Itemid,144/func,view/id,152/catid,2/

Re: Tank set-up advice,com_simpleboard/Itemid,144/func,view/id,715/catid,2

Re:New with lots of questions 🙂,com_simpleboard/Itemid,144/func,view/catid,2/id,1050/#1050

Please let us know if you have any other questions that haven’t been covered in those previous discussions, Carrie!

Best of luck with your new seahorse tank, Carrie!

Happy Trails!
Pete Giwojna

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