Re:Dwarf Seahorses for a beginner

Pete Giwojna

Dear hero:

Yes, sir, I agree — whenever possible, I recommend raising the newborn dwarf seahorses in a nursery tank of their own separate from the adults.

It’s true that newborn dwarf seahorses eat the same food as the adults and can be raised right alongside their parents in the same aquarium if need be, but for best results, you need to alter your feeding regimen and maintenance schedule somewhat when you are raising the fry. For example, the adults do well with two feedings a day, but the babies require more frequent feeding and will do better if they are fed 3-5 times a day. Ideally, newly-hatched brawling shrimp should be available to the young at all times so they can feed at their leisure throughout the day. And when you are feeding more often, you will also need to perform more frequent water changes and siphon fecal pellets up regularly in order to maintain water quality, as discussed below.

Cannibalism is unknown in H. zosterae, and one of the neat things about them is that the fry can often be reared in the main tank right alongside their parents since the newborns eat the same foods as the adults. However, to maximize growth and improve survivorship, the fry should be reared in a separate nursery tank where the hobbyist can maintain better control over their feeding, growth and development (Bull and Mitchell, 2002, p57). A basic benthic nursery with air-operated undergravel or sponge filters works great for this and can be set up in much the same way as the adult tanks. A 1-gallon or 2-gallon goldfish bowl equipped with an undergravel filter and suitable hitching posts makes a fine nursery tank for dwarf seahorses, but of the options you mentioned in your post, hero, I like the 4-gallon aquarium with the built-in undergravel filters the best. However, as you know, the larger water volume in the four-gallon setup would make it more difficult to maintain an adequate feeding density for the newborns. One way around that problem would be to keep the four-gallon aquarium only half-full of saltwater, so that so that it only holds 2 gallons of water. The undergravel filters will still work just as well but the smaller water volume would make it easier to maintain a good feeding density for the young.

Cured ”seahorse trees” make good hitching posts, as do artificial aquarium decorations such as small seafans and soft plastic plants with fine, branching leaves (Giwojna, Jan. 1997). Strips, sections, and cylinders of plastic window screen or the plastic mesh sold in craft stores for needlepoint projects also work well for benthic seahorse fry. Short lengths of polypropylene rope (the kind sold at hardware stores and marine outlets for boating purposes) are another good option for hitching posts in the nursery. They come in many different colors, can be cut to any desired length, and are buoyant so if one end is anchored and the other end is unraveled, they will wave gently in the current like natural plants. (Avoid nylon rope, however — it bleeds in saltwater and will leech color and who knows what else into your tank!) If necessary, the holdfasts can be secured to the bare glass with silicone aquarium cement or suction cups designed for use in marine aquaria, or secured to a piece of coral rubble to anchor them in place.

In this type of simple nursery setup, you stay on top of water quality by making small partial water changes a few times every day while using a length of airline tubing to siphon fecal pellets and dead or uneaten rite shrimp from the bottom of the tank. Nurseries for benthic fry such as dwarf seahorses don’t need to be fancy at all. (Heck, back in the day, my nursery tank for my first dwarf seahorses was an empty mayonnaise jar and even that did the trick as long as I performed partial water changes very regularly in conjunction with siphoning the bottom clean.)

As always, more frequent maintenance is required for the nurseries, however. With heavy, continuous feedings in such a small volume of water, regular siphoning is necessary to maintain water quality (Bull and Mitchell, 2002, p57). Fecal pellets and debris should be siphoned from the nurseries at least twice a day with the deficit made up with new seawater (Bull and Mitchell, 2002, p57). The sponge filters must also be cleaned often as described previously.

Remember that a brood of baby seahorses generates a tremendous amount of waste. Like all babies, seahorse fry exist only to eat and poop. To say they are voracious is a gross understatement — at this stage of their development, the newborns have but one mission in life: to eat and thus to grow. Researchers have found that a single seahorse only a few weeks old can consume 3000-4000 newly hatched brine shrimp in a single day! Milligram for milligram, a great white sharks feeding habits appear downright dainty and positively anorexic compared to a baby seahorse on the prowl for live prey. And as you can imagine, when well-fed fry eat that much, defecation is amazingly rapid, with each newborn producing an average of one fecal pellet every 25-30 minutes. Multiply that by several dozen fry and you can see that it doesn’t take very long for the bottom of your nursery tank to become carpeted with fecal pellets.

Since the nursery tanks have limited filtration, daily water changes are the only way to keep up with the metabolic wastes and oxygen demand of several dozen baby seahorses and the thousands of brine shrimp needed to feed them. The best way to perform the necessary maintenance is to use a length of airline tubing to siphon off the waste that accumulates on the bottom at least twice a day (noon and evening are ideal for this). Replace the water that was removed while siphoning with freshly mixed saltwater that has been pre-adjusted to the same temp and salinity as the nursery tank. Change about 10% of the water each time you siphon the bottom, so that a total of at least 20% of the water in the nursery tanks is exchanged every day.

The benthic fry thrive on newly hatched brine shrimp (Artemia nauplii) with small, frequent feedings that provide live prey throughout the day. They seek out hitching posts from birth, meaning the fry rarely gulp air, floaters and surface huggers are virtually nonexistent, and they are largely immune from the buoyancy problems that so often plague pelagic seahorse fry.

Experienced aquarists often achieve good success rates (better than 20% survival) in rearing H. zosterae to adults using these simple methods (Bull and Mitchell, 2002, p57). Those figures certainly can be improved, but realistically, in order to increase survivorship much higher you must consider other food sources for the fry and be willing to explore more sophisticated nursery tanks.

Marine copepods are the ideal food for dwarf seahorse fry. Field studies have shown that copepods comprise the bulk of the diet of Hippocampus zosterae in the wild (Tipton, K. and S. S. Bell. 1988. “Forging patterns of two syngnathid fishes: importance of harpacticoid copepods.” Marine Ecology — Progress Series. Vol. 47: 31-43). Other research projects have shown conclusively that seahorse fry feed on larval copepods grow markedly faster and show increased survivorship that fry raised on newly hatched Artemia (Payne, M.F. and Rippingale, R.F. Rearing West Australian seahorse, Hippocampus subelongatus, juveniles on copepod nauplii and enriched Artemia. Aquaculture 188_2000.353-361). Copepods are natural food source for seahorses in the wild and they are adapted to feeding on them. As a result, they digest copepods much more efficiently and completely than brine shrimp, which is an unnatural food for them that does not exist in the ocean.

If you wanted to try a more sophisticated nursery setup in anticipation of regular broods of dwarf babies, hero, then I would suggest setting up a five-gallon or 10-gallon aquarium as a divided nursery for your dwarf fry. The basic Divided Nursery tank design, which simply involves separating a standard five-gallon or 10-gallon aquarium into two or more different compartments with a common water supply using perforated tank dividers. All of the equipment and filtration goes into one of the resulting compartments while the other compartment(s) serve as the nursery or nurseries for the fry.

The perforated barrier allows water to circulate freely between the compartments while acting as a baffle that greatly dampens the turbulence generated on the equipment side.

It is also very effective at keeping newly hatched brine shrimp confined to the fry’s nursery compartment, especially if two or three of the perforated plastic dividers are sandwiched together side-by-side with a small 1/8-1/4-inch gap between them, forming a double barrier (Abbott, 2003). In your case, hero, I would go one step further and cover the perforated tank dividers with plastic window screen or better yet the plastic mesh sold in craft stores for needlepoint projects to increase the effectiveness of the barriers (Abbott, 2003). Then I would darken the equipment side and position a strip reflector or table lamp at the end of the nursery compartment opposite the filtration side, in order to draw the baby brine shrimp (bbs) away from the tank divider and filters, while concentrating the bbs in a smaller area so the fry can feed more efficiently (Abbott, 2003).

All of the gear is thus isolated on one side of the partition safely away from the fry and their food. In the nursery setup, the bulk of the tank is reserved for the filtration equipment, with the smaller compartment housing the newborn dwarf seahorses and their live food (Artemia nauplii and/or larval copepods). The larger volume of water a divided tank provides gives the nursery greater stability as far as fluctuations in temperature and pH go, makes it easier to maintain optimum water quality, and increases your margin for error accordingly (Abbott, 2003). With the tank divided in this way, any sort of mechanical, chemical or biological filtration you care to provide can be safely operated in the equipment area without disturbing the delicate fry in the nursery area (Abbott, 2003). The developing young thus enjoy all the benefits that better filtration and a large water volume can provide, while being confined in a smaller nursery compartment, making it easy to maintain an adequate feeding density (Abbott, 2003).

To provide efficient biofiltration for the divided nursery, hero, I would install a fluidized sand filter on the equipment side. Fluidized bed filters use a fine sand media suspended in upflowing water currents that provides a tremendous amount of surface area for beneficial bacteria to grow, and allows the filter to nitrify large amounts of ammonia while maintaining high overall water quality and stability. There would be no ammonia spikes with such a nursery.

Further details on breeding and rearing your Pixies are available in Alisa Abbott’s guidebook titled Complete Guide to Dwarf Seahorses in the Aquarium. That’s one book every Pixie owner and dwarf seahorse keeper should have on hand. I’ve proofed Alisa’s dwarf seahorse book for TFH publications and wrote the preface for it, and I highly recommend it!

When it comes to the main tank for the adult dwarf seahorses, hero, there are all sorts of options that you can consider, as we have already discussed off list as well as in previous posts. Here are some posts from other dwarf seahorse keepers explaining the type of tanks they prefer and how they modified the filters for those aquariums to make them suitable for their pint-size pygmy ponies:

> I’m having a hard time keeping my dwarfs from getting stuck to my
> recirculating pump supply opening in the back wall of my nano….Any ideas
> how to fix this problem?

Simplest method:
Hang a rectangular sponge suspended on strings over the edge of the
tank… let sponge be sucked against the intake.

Engineered method:
Silicone a plastic cover over the intake slots. This plastic cover
will need a hole drilled in it just big enough to retrofit part of the
elbow of an AZOO bio Sponge filter to it. The sponge will keep the
horselets and brinies from being run through the filter.

Ken McGuire’s Dwarf Pico Tank

In a message dated 7/9/2008 11:42:58 A.M. Central Daylight Time, [email protected] writes:
You might consider a 3 gallon Pico Tope at Drs Foster and Smith. It
comes with a good filter. An Azoo Bio Sponge fits the intake tube
perfectly. You will need to modify the sponge so it will fit
between the tube and the glass. Some brineys still get in the
sponge, but it is cuts way down on the briney loss due to
filtration, and the filter is just the right size for a 3 gallon to
keep the shrimp moving but slow enough so the seahorses can feed.

I wouldnt have any other set up for dwarves now.
I tried a 10, and a 2.5 gallon set up. The 3 Gallon seems to be the
easiest to use for small herds of a dozen or less. I recommend only
6 or 12 dwarfs for a 3 gallon. They display well in this tank.
Easy Filtration System for Dwarf Seahorses

I like to use the Azoo palm filter with a Poly filter in it instead of
the using the little fitler pads that come with it. The flow of the
filter is too powerful for my tastes, so I put a baffel in the J tube
to slow the water down. A sponge filter on the intake keeps the baby
brine from being sucked in.

See my design here:


I am happy with this design and thought others might like to see it.


Susan’s Tips for Raising Dwarf Seahorses (Hippocampus zosterae)

Hi Ricky,

We raise the dwarfs, as we call them. They are hardier than the big guys in my opinion, the only problem is keeping up with raising the baby brine.

We have had them in a 10 gallon for the past year and are ready to move them into a 15 real soon, they had a lot of babies this past year.

We use an Aqua Clear filter, the #20, on low. I put a sponge filter around the intake, and shut the filter off and clean the sponge everyday. When we move them into the 15, we’ll use the same filter, only set on high. Sometimes they like to play in the current and sometimes they just go to the other side of the tank where we have a couple seahorse tree’s. You’ve probably seen them at the lfs. We have one natural tree as well.

Also, on that side of the tank, I have a solid air tube that I took from one of those sponge filters. Just took the sponge off and use the air to keep anything from accumulating at the top.

When it is bright out, I keep the light off of the tank because otherwise the bbs go to the top and the dwarfs being lazy, like the food to come to them.

Keep your eyes out for hydroids as they love the same environment as the dwarfs. Panacur works great, and we haven’t had a problem since.

Happy to help with any other questions.

PS. I forgot to mention that I enrich the bbs with teeny amount of Vibrance. Susan

rlbailey2005 wrote:
Hey Everyone! I just got back last week from Florida and I went to the
Tampa Aquarium. They had a marvellous display of seahorses. I believe
their were six different species in all. I also got to see my first
tank of Pixies in person and are they cute. I have read up on them
somewhat, mainly that they eat only live brine shrimp and have small
tank requirements and very very low water circulation from a pump. I
have thought about setting up a 10 gallon tank for some and was
wondering what kind of filtration I should use and how many I could
keep in a 10 gallon tank. I think its cool that the babies can grow up
right with thier parents. I also thought about getting a 10 gallon
eclipse system for them but I have not decided which would be best. So
that’s where the group comes in. I would like to get everyones opinion
on this subject and would especially like to hear from those that have
pixies. Thanks

"D’s" Tips for Raising Dwarf Seahorses


Have you convinced Tonya to join you in this adventure ;>).

By no stretch of anyone’s imagination am I an expert but I created a
small tank set up that was (and still is for my mother) successful for
a small shield of dwarves that may be of interest. It is the only set
up where I was able to raise to adult any of the dwarf babies.

I found a small 1.5 gallon (I think they are actually listed as 2
gallon but they do not hold that much) hexagonal acrylic tank. They
are under $30 at Petsmart and made of VERY scratch resistent acrylic.
They come with a light fixture and single tube undergravel filter

I added a Red Sea cascading filter (made for Nanos and is very
impressive for this sized tank with an adjustable flow control and a
slot for filtration that can easily use a piece of any media cut to
fit or small charcoal bag).

I run the filter intake into the under gravel and block off the gap
with a sponge (the horses WILL get into the tube if you do not block
the gap and you must close it off when cleaning the intake tube). The
flat acrylic cover needs modification to fit the cascade filter (it
could be left off but it protects the light from the saltwater) so I
cut it to the size of the light cover(two straight cuts – chop saw
does it quickly), leaving gaps between the front and back of the light
fixture. The front gap is perfect for feeding with the little cups
from the brine shrimp hatchers I use from Brine Shrimp Direct (see
prior posts or email me if you would like details). I also cut a
round hole in the light fixture top (a little tricky but I used a hole
saw bit and drill) to allow more heat to escape since I use a 50/50
actinic instead of the bulb that comes with it. The light fixture
uses a standard screw bulb so there is plenty of room for
experimentation. I also had to make a small nick on the back of the
light hood to accomodate the filter down tube but it was a minimal cut
and the unit looks quite presentable.

This was my most successful set up for the dwarves and the only one
where I successfully raised any babies. I did use a piece of live
rock (pretreated with worm killer) for the setup given to my mother at
Christmas and there have never been hydroids. It needs much more
frequent water changes than a larger tank – about 1 cup a day but the
water change takes less time than feeding. Algae growth is also a
problem but that is more likely my lighting than anything directly
related to the tank. Not using live rock should also help with algae

I no longer raise the dwarves for myself but help maintain the set up
for my mother (I provide water, shrimp eggs and occassional tank
cleaning). However, I still use two of these little tanks for varying
adventures. Currently, I have a small slipper lobster and serpent
star in one and keep an "undesireables" tank with the other (aptasia
can be interesting – OUTSIDE of your reef/horse tanks ;>).


That’s the current thinking on modified aquariums for dwarf seahorses, hero. Some hobbyists also report good success using the Biorb aquarium system systems for dwarf seahorses. The built-in filtration system in the biOrbs functions primarily as an undergravel filter, supplemented with mechanical and chemical filtration cartridges, and I have often Dwarf seahorses successfully with undergravels.

My only concern about the Biorb is the light fixture. The halogen bulb may give off a significant amount of heat, and with the top of the tank capped off like that, it’s possible that the light might raise the aquarium temperature to undesirable levels after it’s been running all day. I’ve had no experience with the Biorb so I don’t know if that’s the case or not, but the possibility does concern me. However, the top includes air vents and a heat exchange system to help cool the tank, so that may effectively prevent overheating. And, of course, even the heat given off from the lamp should prove to be a problem, it could be easily solved by removing the light fixture/top and allowing the ambient room light or a nearby table lamp to provide the illumination.

At any rate, it certainly looks like it would work well and I wouldn’t hesitate to give it a try. A whole range of accessories are available for the tanks and they are the right size to accommodate the whole herd of dwarf seahorses. Yet they are not so large so large that it would be overly difficult to maintain an adequate feeding density of baby brine shrimp.

Okay, hero, those are some other ideas you might want to keep in mind when you are planning your dwarf seahorse set up and deciding what type of filter to go with the larger tank, and how to modify it to make it safe for the dwarfs.

Best wishes with all your fishes!

Pete Giwojna

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