Home | Aquarium Livestock | The Natural History and Captive Care of Native Seahorses – the Dwarf Seahorse, Hippocampus zosterae

The Natural History and Captive Care of Native Seahorses – the Dwarf Seahorse, Hippocampus zosterae

Please welcome back Frank Indiviglio with another excellent article.

Introduction – A Most Captivating Fish
Seahorses, armor-plated and prehensile-tailed, and equipped with independently-moving eyes and fins that flutter like wings, seem to stretch the limit of what might conceivably be called “a fish”.  Add to this the phenomenon of “male pregnancy” (the male incubates the eggs in a pouch and adjusts the salinity of the water therein as needed; please see my article posted on this blog on June 27, 2008 for more details) and the fact that seahorses change color and can grow and discard filamentous appendages, and you can easily see why they have long attracted marine aquarists.  All of the nearly 130 species (Family Syngnathidae) are, however, strict live food specialists, and rarely thrive on the brine shrimp-based diet commonly offered to them in captivity.

The two species highlighted in this article (Please see Part I, The Atlantic Seahorse, published last week) were chosen because, of all, they are the most likely to do well on diets that are within the means of most aquarists.  Please do not be tempted to try other species until you are well-experienced with the following animals.  I will focus here on points unique to seahorse husbandry – water quality and filtration should be managed as for other marine fishes (please see related articles posted on this blog).
Dwarf Seahorse, Hippocampus zosterae

Description and Habitat
“Seapony” might be a more appropriate name for this diminutive creature, which, at an adult length of 0.9 inches, is only slightly larger than the smallest known species, Denise’s pygmy seahorse (please see below).  Ranging from Florida to the Bahamas, the dwarf seahorse may be white, yellow, green or black in color.  It dwells in sea grass beds, so much so that the species name, “zosterae”, is drawn from that of the plant with which it is most often associated.  Northern populations were formerly considered to be a separate species, H. regulus.

An Ideal “First Seahorse”
In sharp contrast to larger fishes, dwarf seahorses offer us the opportunity to observe nearly all of their natural behaviors in captivity.  Due to their small size, they adjust readily to the confines of aquarium life.  Three pairs in a 15 gallon tank will reward you with a display of activities not often observed among captive seahorses of other species.   As a consequence, their captive husbandry is well understood, and many specimens in the trade are commercially produced.  This is an important consideration at a time when many seahorse species are in sharp decline (please see below).

Interest in this charming creature peaked here in the 1960’s and early 70’s, when they were advertised for sale in the backs of magazines.  My grandfather, who kept marine fishes even before that time, so aroused my interest in them that I eventually wrote a book on the care and natural history of seahorses  (please see below).

The Key to Feeding Dwarf Seahorses
Dwarf seahorses are one of the only seahorse species that will thrive on a diet consisting solely of enriched brine shrimp.  They will, however, appreciate an occasional meal of tiny, wild caught invertebrates – thin meshed “plankton nets,” (available from biological supply houses) drawn through shallow marine waters will yield a wealth of valuable food items.  “Enriched” brine shrimp are those that have been allowed to feed for a few days before themselves being given to the seahorses.  This process increases the shrimps’ nutritional value, and is indispensable if one is to succeed in keeping dwarf seahorses.  Therefore, brine shrimp intended as seahorse food should be given Brightwell Aquatic’s Phyto-Green, or a similar product, for several days.

Breeding and Other Considerations
In common with all their relatives, dwarf seahorses require calm water and suitable “hitching posts” upon which to wrap their tails.  There is some evidence that wild seahorses consistently utilize the same hitching sites, so their aquarium’s décor should not be re-arranged once they have been introduced.  Captive reproduction is a definite possibility – the tiny young can take only newly-hatched brine shrimp, so be sure to set up a brine shrimp hatchery  in advance.

Tiny, Newly Discovered Specialists
The Pygmy Seahorse, Hippocampus bargibanti, first described in 1970, seems to live on only 2 species of gorgonians (soft corals) of the genus Muricella.  So closely does it resemble the coral’s polyps that the individual which led to the first description of the species was not discovered until it was seen on a coral that had been placed in an aquarium several days earlier!  At 0.8 inches in length, it was the smallest known species until the discovery, in 2003, of Indonesia’s Denise’s pygmy seahorse.  Adults of this minute creature are a mere 0.6 inches long.

As mentioned, I became so enamored of these unique fishes that I wrote a book on their care and natural history – if you have a chance to read it, please forward your thoughts and suggestions to me.   Until then, please write in with your questions and comments.  Thanks, until next time, Frank.

Project Seahorse is the world’s premier seahorse conservation and research organization.  A wealth of information is available at their web site:

http://seahorse.fisheries.ubc.ca/who.html

Thanks for the great article Frank,

Until Next Time,

Dave

4 comments

  1. avatar

    Hello,
    I read this article and your name seemed familiar. I realized that I have your seahorse book also. It has been very useful to us. I have experience with many marine fishes and other animals of all kinds but seahorses have always given me more trouble than most, so any information you could send would be appreciated. I found like you that dwarf seahorses do better than some of the larger and more expensive kinds. I am using the product you mentioned in this article, phytogreen, as brine shrimp food.My husband had Selco recommended to him – would it be good to used this, or both, also?

    We sometimes collect at a bay in NJ and often find pipefish which I believe is the northern pipefish. Your book and article mentions these as doing well with seahorses. Do you think they might live with dwarf seahorses, or do they need colder water. Also, we use mainly brine shrimp as live foos..can pipefish adjust to frozen food; is brine shrimp enough for them?

    We had a few local hermit crabs as you suggested in the book, but found one eating a seahorse, and so released them just to be on the safe side. Could the hermit crab have killed the seahorse? Sorry for so many questions, thank you.

  2. avatar

    Hello, Frank Indiviglio here. Thanks for your interest in our blog.

    Selco is a fine product for nutrient-loading brine shrimp, rotifers and similar creatures.

    The pipefish that you encounter in NJ are almost certainly northern pipefish, Syngnathus fuscus, as no other species regularly occurs in the area. The pipefish overlaps with dwarf seahorses in the southern portion of their range, and will do fine in the warmer temperatures needed by the seahorses. I have kept northern pipefish that were collected as adults for approximately 18 months on a diet composed largely of enriched brine shrimp. It seems to be a good diet for them…it’s often easy to find very young ones in late summer – raising some from a young age on brine shrimp would be a good way to judge the diet’s value. I did not try frozen foods with them, but that is a very good idea. The pipefish are alert predators, and might take to it. My only caution re keeping them with dwarf seahorses would be to monitor food intake carefully – I think the pipefish will prove to be more effective hunters, and may out-compete the seahorses at feeding time.

    Hermit crabs are not very effective predators in general, but a very large individual might be able to overcome a dwarf seahorse. It’s more likely that the crab was scavenging an already dead seahorse, but stick to very small individuals in your tank. These should be quite easy to collect in the waters inhabited by the pipefish.

    Please be in touch if you need further information, and good luck…spring collecting season will be here eventually…. Best regards, Frank Indiviglio.

  3. avatar
    Hye Jeong Grenier

    Hello,
    I’m having difficulty adjusting the flow rate on the 2 different types of filters that I use in my seahorse aquarium. The current if blowing the seahorse around, no matterhow I try to slow it. In the spring I am planning to add pipefish, which also need slower water I believe. I have an undergravel plate already in place, and am thinking to give it a try, do you have any opinion on undergravel filters?

  4. avatar

    Hello, Frank Indiviglio here. Thanks for your interest in our blog.

    You are correct in that both seahorses and pipefish swim and feed more effectively in fairly calm water.

    Undergravel filters have fallen out of favor with aquarists lately, but, when properly maintained, they are extremely effective and simple to operate. I have used them as the sole filtration method on large exhibits housing adult bluegill sunfishes, bullhead catfish, musk turtles, water snakes and other creatures that are very “hard” on filtration systems with great results. A number of public aquariums still rely mainly or even solely upon undergravel filters in major exhibits.

    It is important that you keep water circulating through the entire gravel bed…fine sand sometimes becomes compacted and disrupts water flow. You can avoid this by mixing in coral-based substrates into the sand.

    Vacuuming the gravel bed regularly (i.e. when you do monthly water changes) with an automatic or manual gravel cleaner is absolutely essential, in order to remove detritus that has been drawn into the substrate bed. You may wish to turn your other filter on for a time after doing this, so as to remove any of the detritus you raised while vacuuming.

    Be sure that your air pump is of sufficient strength as regards the size of your aquarium…outflow from the return tubes should be vigorous (the water is returned upwards, and so will not disturb the fish). As undergravel filters rely primarily upon aerobic bacterial action, and these bacteria expire rapidly without oxygen, it is a good idea to have a battery operated air pump on hand, in the event of a power outage.

    Secure holdfasts are very important to seahorses…artificial coral is ideal. Local pipefishes are usually associated with eel grass beds, and need dense plantings of similar species in order to feel secure (note their body shape, they are very hard to see among eel grass). Artificial Vallisineria is readily used as a retreat by pipefishes and has worked well in my aquariums.

    Best regards, Frank Indiviglio.

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About Frank Indiviglio

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Being born with a deep interest in animals might seem unfortunate for a native Bronxite , but my family encouraged my interest and the menagerie that sprung from it. Jobs with pet stores and importers had me caring for a fantastic assortment of reptiles and amphibians. After a detour as a lawyer, I was hired as a Bronx Zoo animal keeper and was soon caring for gharials, goliath frogs, king cobras and everything in-between. Research has taken me in pursuit of anacondas, Orinoco crocodiles and other animals in locales ranging from Venezuela’s llanos to Tortuguero’s beaches. Now, after 20+ years with the Bronx Zoo, I am a consultant for several zoos and museums. I have spent time in Japan, and often exchange ideas with zoologists there. I have written books on salamanders, geckos and other “herps”, discussed reptile-keeping on television and presented papers at conferences. A Master’s Degree in biology has led to teaching opportunities. My work puts me in contact with thousands of hobbyists keeping an array of pets. Without fail, I have learned much from them and hope, dear readers, that you will be generous in sharing your thoughts on this blog and web site. For a complete biography of my experience click here.