The Dwarf Seahorse (Hippocampus zosterae) is one of the
smallest seahorses with an adult height of 1.5 to 2 inches. Dwarves
need daily feedings of live brine shrimp. Dwarves readily breed in your
tank and the fry can be left in the parent tank to grow up
Dwarfs do best in smaller tanks. A tank can be anything from 1 to
10 gallons (which will easily house 50 or more dwarves). Dwarves do not
chase or hunt prey; they remain hitched and wait for food to drift by
within reach. The larger the tank, the more brine it takes to create
the necessary “snowstorm” effect and without a large number of dwarves,
too much uneaten food remains. You would need at least 10 dwarves for a
10 gallon tank. I recommend a 5 gallon or less for most
people. A 2-gallon tank can easily hold 6 dwarves and a few fry.
Seahorses spend most of their day hitched to plants so they will need
plastic plants, live marine plants, or macros such as Caulerpa to hold
Tank temperature needs to be as stable as possible with no more then
a 3-4 degree swing during a day. Recommended temperature is between 68
-75F with spikes no higher than 78. Higher temperatures encourage the
proliferation of bacteria and are not needed for the seahorses.
Intake for any filter must be covered with sponge to avoid sucking up
or trapping dwarves and fry. Be careful of using filter materials to
cover intakes as many materials have a “Velcro” effect with the tiny
spikes on the horses. Impellers can be trimmed to adjust flow if
needed. Also be aware of the output to be sure that it will not cause
problems for the dwarves.
Dwarves do fine in normal salinity but reducing salinity to 1.019 can
be helpful in keeping bacteria and parasites at a minimum. Ammonia and
Nitrites should be undetectable and Nitrates should not exceed 40. Ph
should be within the 8.1-8.3 range
Feed your dwarves daily with live brine. The eggs should be
decapped in bleach to remove the outer shell – decapped brine are more
nutritious and are hydroid free. You can decap enough eggs for about 3
weeks at a time and store them in the refrigerator or you can purchase
decapped eggs if you don’t want to do it yourself. Excellent
instruction for decapping and hatching brine can be found at
http://www.saseahorse.com/seahorse.htm. New hatch brine should be
provided most of the time but can alternate with older enriched brine.
Newborn fry will require new hatch brine daily for at least the first
week of life. Do not use an “in tank” hatchery as the hatch water is
a bacterial soup – in fact, brine should be rinsed in freshwater prior
to adding it to the tank. Never add unhatched eggs, (even
decapped) directly to the tank.
Note: Brine shrimp nets that look like netting don’t work – get the
ones that look like white cloth. Also, a turkey baster is a great way
to move or remove brine and even fry.
There are few appropriate tankmates. Dwarves are easily out
competed for food and make obvious targets to be picked on. The fry
are very small and vulnerable. Even a friendly but fast moving tankmate
can cause stress for a dwarf. Volcanic red shrimp (from Hawaii) and
snails are good. Some people keep very small hermits with dwarves,
however, I had one bad experience with a hermit and have banished them
from my tanks. Some corals can be kept with dwarves but you should
avoid any coral with a sting and any that could possibly eat a dwarf
fry. Also keep in mind that the lighting and temperature needs
must be compatible
Hydroids and other hazards
Even with a proper setup and appropriate tankmates there are more
threats to these tiny seahorses. As you setup your tank you will
want to be sure you are prepared to deal with these hazards.
HYDROIDS: Hydroids are present in most marine tanks - in small
numbers they are not very visible and are mostly unnoticed and of no
concern to most marine aquarium keepers. However, when large
amounts of brine shrimp are introduced the hydroid population can expand
very quickly and the sting from a hydroid can kill even an adult dwarf.
Hydroids come in a few varieties. There are
the tiny jellyfish looking ones.. when swimming they appear to be
jellyfish and when on the glass they are described as dots with legs.. a
center dot with 8 or 9 tentacle dots in a circle. There are the cobweb
looking ones... usually attached to the glass or objects in the tank but
sometimes free-floating - these are very fine strands. I've also heard of
a "pink fuzzy stuff" type but I have never seen these.
Fenbendazole (Panacur) kills hydroids.
Panacur is actually sold as a dewormer for pets or livestock but is
usually impossible to find locally. You can buy it and other medications
http://www.seahorsesource.com. What I did was set up the tank and cycled it, added
everything I wanted in it then dosed the 3 days with the last day being
the day I added the dwarfs - since my brood stock was to be wildcaught
and they often bring the hydroids with them. Captive bred dwarves should
be hydroid free. You can treat with the
dwarves in the tank. Panacur will not harm the biofilter, fish, macros,
pods, or shrimp. Panacur will kill some types of snails (particularly
astrea), fans, worms of any kind, most if not all soft corals,
gorgonians, all stars, etc. The effect on these creatures can last over
There is a lot of hydroid/panacur information at www.seahorse.org - a search
there will give you all the known details.
AIPTASIA: Aiptasia can also easily kill a dwarf. You
will need to make sure the tank is clear of them.
PARASITES & BACTERIA: Wild caught dwarfs are more
likely to have problems with these but the possibility is always there.
You should have a supply of antibiotics and formalin on hand to respond
quickly to any problems. Specific diagnosis and dosing information
can be obtained quickly by posting a problem at
http://www.seahorse.org/ in the
AMPHIPODS: Large amphipods have been known to kill dwarf
fry and even larger dwarves.