Reply To: Hippocampus fisheri care

Pete Giwojna

Dear Andrea:

In my experience, seahorses tolerate formalin (and most other medications) as well as most other marine fishes, so you may certainly include formalin as part of your quarantine procedure.

However, whenever you use formalin it is important to observe the necessary precautions, as discussed below in more detail:

FORMALIN Short-Term BATH Dosage and Preparation Instructions
Active Ingredient: 37% Formaldehyde
Indication: external parasites
Brand Names: Formalin, Formalin-MS
1. Do NOT use Formalin that has a white residue at the bottom of the bottle. White residue
indicates the presence of Paraformaldehyde which is very toxic.
2. “Formalin 3” by Kordon contains only 3% Formaldehyde. Dosing instructions will need to be modified if using this product.
• Fill a small tank with aged, aerated, dechlorinated marine water. Match the pH, temperature, and salinity to that of the tank the Seahorse is currently in.
• Add an artifical hitch and 1–2 vigorously bubbling airlines. Formalin reduces dissolved O2 so heavy aeration is required.
• Add 1ml/cc of Formalin per one gallon (3.8 liters) of tank water. Allow several minutes for the Formalin to disperse.
• Place the Seahorse into the dip water for 45–60 minutes unless it is showing signs of an adverse reaction. If the Seahorse cannot tolerate the Formalin dip, immediately move it back to the hospital tank.
• Observe the Seahorse for 24hrs for signs of improvement.

Although the Hawaiian pelagic pygmy seahorses (Hippocampus fisheri) are quite small even as adults, Andrea, they require much larger aquariums than one would think in order to thrive in captivity because of their deep ocean habitat and well-developed swimming ability.

Ideally, you want to find an aquarium of 30-40 gallons that is 30-36 inches tall, and don’t even consider a tank that’s not at least 24 inches tall at the bare minimum. For best results, I would suggest establishing a column tank or hexagonal tank that is 36 inches tall and holds at least 30 gallons of water, with a very efficient filtration system.

Several pairs of Hippocampus fisheri can be kept in an aquarium of 30-40 gallons.

I don’t have many new suggestions to help the juveniles make the transition to frozen foods, Andrea, but you might consider trying the Mini Marine Mysis by H2O Life. These nutritious frozen Mysis are small enough for many of the juveniles to take whole and intact, rather than having to be chopped up for shaved, and they may stimulate a stronger feeding response from the juveniles.

If they do not, then you’ll have to try a little trickery to get the juveniles to accept them, Andrea. By this I mean that you could try offering them live Mysis to begin with, which all seahorses find irresistible. The Mysidopsis offered by Sachs System Aquaculture are small enough to be eaten by 10-week juveniles, and they are inexpensive enough that you could set up a small tank to hold the live Mysis, and then begin offering them to the 10-week olds. If they eat them readily – and I suspect that they will – then you can gradually begin mixing in some of the H2O Life Mini Marine Mysis that you have carefully thawed and prepared, among the live Mysis. In their eagerness to slurp up the live Mysis, the 10-week old juveniles will also begin slurping up the lifelike frozen Mini Marine Mysis as well, and then you can gradually increase the proportion of the frozen Mini Marine Mysis that you add to their feedings over the next couple of weeks until they are eating primarily the H2O Life Mini Marine Mysis.

Once one of the juveniles begins accepting the frozen Mini Marine Mysis readily, the others will often learn to do so simply by following his example, and when that happens, you will have this problem licked.

Sachs Systems Aquaculture offers live Mysis in lots ranging anywhere from 100 to 5000 for very reasonable prices which include the cost of priority shipping. For example, you can obtain 200 live Mysidopsis bahia for $35 (priority shipping included) from Sachs and see if your 10-week juveniles gobble them up or not. Just copy the following URL, paste it in your web browser, and press the “Enter” key, and it will take you to the right page to order the live Mysis from Sachs:

Another option that you can consider if the juveniles continue to refuse anything but the newly hatched baby brine shrimp (Artemia nauplii), Andrea, is to begin offering them older and older brine shrimp at more advanced instars over a period of weeks. That way they can continue to eat the baby brine shrimp, but you will be providing them with larger Artemia nauplii at more advanced stages of development until they are eventually eating adult brine shrimp. Once they are taking the adult brine shrimp, they should also be ready to accept the H2O Life Mini Marine Mysis, which are not much larger than the adult brine shrimp are, making the transition very easy at that point.

This is what I typically advise home breeders regarding weaning their juveniles onto frozen foods, Andrea:

Making the Transition to Frozen Foods

The current thinking is that the fry can remain on a steady diet of newly hatched Artemia until you are ready to begin weaning them onto a diet of frozen foods (usually minced Mysids and/or Cyclop-eeze). Aquaculturists are now converting the fry to frozen foods earlier than ever, often beginning around 3-4 weeks old. Jeff Mitchell reports that the fry are healthier and grow faster the sooner they make the transition to enriched frozen foods, and he expects the young seahorses to have made the transition to frozen foods by the age of 4-1/2 weeks.

I generally have the best results using frozen Mysis. The best way to prepare the Mysis for the juvenile seahorses is to mince the frozen Mysis coarsely rather than putting it through a blender. How fine or coarse you need to chop it depends on the size of your fry, since you want to wind up with bite-size pieces of Mysis. Initially, many breeders prefer to shave small pieces of Mysis off of a cube while it’s still frozen.

The frozen Mysis that works best for most hobbyists is Hikari in frozen blocks rather than trays. The Hikari Mysis is much smaller than Piscine Energetics Mysis relicta and that makes it easier to shave off bite-sized pieces for the young seahorses. Some hobbyists report even better results using the new Mini Mysis offered by H2O Life, which is small enough that it often doesn’t need to be minced or shaved before offering it to the juveniles.

When it comes to shaving the Mysis, a technique that works well for many home hobbyists is to use a potato peeler to shave off bits of the Hikari Mysis from a frozen block, and then use a single edged razor blade to further mince the frozen bits the potato peeler has removed.

Try offering the minced Mysis exclusively for their first feeding of the day when the youngsters are the hungriest. Watch the juveniles closely to see if any of them begin to pick at the minced Mysis or pick it up from the bottom. If they still aren’t having any of it, siphon up the uneaten frozen Mysis after about half an hour and offer them newly hatched brine shrimp soaked in Mysis juice so that they have something to eat, and intermingle some freshly minced Hikari frozen Mysis or Cyclop-eeze in with the bbs.

When the fry have grown a little larger and can accommodate bigger pieces of Mysis, I find it convenient to carefully thaw whole Mysis individually and then carefully chop them into several pieces. Or the Mini Mysis by H2O Life can be fed to the larger juveniles whole and intact, if you can obtain it.

Either way, it is very important to be extra diligent about vacuuming up leftovers (and any fecal pellets) while the fry are making the transition to frozen Mysis. Otherwise, the minced Mysis that doesn’t get eaten right away while it’s still suspended in the water column or shortly after it has settled on the bottom will begin to degrade the water quality in your nursery tank. (Adding two drops of 30% formalin per gallon will help to keep the nursery tank more sanitary when using minced Mysis or converting the juveniles to a staple diet of frozen foods.)

It’s important to overlap the fry food when they are making the transition. Offer them shaved or minced Mysis along with the newly hatched brine shrimp they are accustomed to eating. (Many times it’s better to offer the minced Mysis first, while the fry is still the hungriest, and then add the baby brine shrimp.) Once they begin eating the bits of frozen Mysis well, gradually increase the amount of minced Mysis and decreased the amount of baby brine shrimp you offer at every feeding until they are finally eating the shaved Mysis almost entirely.

Overlapping the feedings this way, offering newly-hatched brine shrimp as usual along with just a little frozen Mysis at first, assures that there is familiar food available to the fry while they are making the transition and makes sure that the slow learners still get enough to eat.

Some hobbyists find it helpful to begin soaking the newly hatched brine shrimp in Mysis juice for a week or two before they actually began offering the bits of minced Mysis along with the bbs. That way, the juveniles get used to the scent of the frozen Mysis and associate it with food before you start to add the bits of frozen Mysis.

Here’s a previous message from Patti that describes how she weaned her erectus fry onto frozen to Hikari Mysis:

[open quote]
I’m wondering if nutrition is your problem.
Could you train them onto frozen mysis? My 4 week old erectus are eating shaved Hikari frozen mysis already. They started not eating much of the BBS and looking around the bottom of the bowl. I enriched the shaved mysis w/Vibrance & put it in the bowl. It goes to the bottom and they’re on the hunt. They’ll look at it a good while and then snick. It only took 1 day to train them. I swish it around a little at first to get them interested.

I think the mysis is better for them nutritionally and they don’t have to spend so much energy eating all those tiny BBS. Give it a try. It may take a few days. I gave mine the mysis 1st – before adding the BBS. That way they were pretty hungry. Then I gave them some BBS for desert to make sure each one got something to eat if they weren’t eating enough mysis yet.
Patti [close quote]

Notice that Patti’s erectus fry were all hitching and beginning to look around on the bottom for things to eat, indicating that they were ready to give up their planktonic existence (i.e., the high-risk pelagic phase) and make the transition from live brine shrimp suspended in the water column to frozen foods.

Other breeders go a step further and begin adding a little of the minced Mysis to their nursery tanks with the newborns right from the start to help build up their intestinal flora and ultimately enable them to better digest the frozen Mysis when they start eating it. They feel that this helps the babies get them used to the scent of the Mysis and conditions them to associate it with food, which helps to make the transition from live food to frozen Mysis easier later on when they’re the right age.

For example, here’s how Neil Garrick-Maidment, a very successful breeder in the UK, describes this technique:

Hi Peter and all,

I tend to put in a very small amount of finely chopped mysis in with the fry from day 1. The idea behind this is to create a bacterial soup in the fry water to help load the fry gut with the right bacteria to break up the mysis shrimp which tends to be quite hard. It makes it easier to get them to switch to dead mysis later on BUT it is crucial to clean the tank daily and water change to stop a problem with disease..

Neil Garrick-Maidment

Cyclop-eeze is also worth considering when weaning the youngsters onto frozen fare. When the juveniles are the right age, don’t hesitate to try them on frozen Cyclop-eeze first if you aren’t having any luck with the frozen Mysis. Lelia Taylor is one hobbyist who has had good results using the Cyclop-eeze, as she described below:

<open quote>
I have had success placing BBS in Cyclop-eeze, then feeding the mixture to my babies. They readily take the Cyclop-eeze. As they get bigger I add frozen, enriched brine shrimp. they began eating the frozen food immediately. Using the same principle, I began adding Mysid shrimp, along with the brine shrimp and Cyclop-eeze. I have found, even very young babies, will pick the larger pieces of Mysid shrimp, into bite sized pieces. I have also had success culturing copepods in my baby and grow up tanks. The babies readily feed on these, as well. <close quote>

Hobbyists who have tried The Cyclop-eeze for their juveniles are unanimous in saying that the frozen Cyclop-eeze is far superior than the freeze dried product for this purpose. They report that the bars of frozen Cyclop-eeze in particular work well because they will shed copious amounts of the bite-size frozen cyclops into the water.

Bonus tip: adding one or two older juveniles that are already eating the frozen Mysis well to the nursery tank along with the inexperienced fry in order to act as their mentors can hasten the transition. Many hobbyists report that fry learn to take frozen minced mysids much faster and easier when they are provided with teachers to show them the way. These teachers are usually a few of the older fry from a previous brood, which have already become proficient at feeding on the frozen mysids (Liisa Coit, pers. com.). The younger fry are quick to copy them, learning from their example.

Okay, Andrea, that’s the quick rundown on rearing seahorses and eventually weaning them onto a diet of frozen Mysis.

Best wishes with all your fishes!

Pete Giwojna, Ocean Rider Text Support

America's Only Seahorse Aqua-Farm and One of Hawaii's Most Popular Attractions

Ocean Rider seahorse farm is a consistent Trip Advisor Certificate of Excellence Award Winner and "Top 10 Things To Do" Kona, Hawaii attraction. Our "Magical Seahorse Tours" are educational and fun for the whole family.

Tour tickets are available for Purchase On-Line. Space is limited and subject to availability.

small seahorse Ocean Rider, Inc. is an Organic Hawaiian-Based Seahorse Aqua-Farm & Aquarium that Follows Strict Good Farming Practices in Raising Seahorses and Other Aquatic Life.

Seahorse Hawaii Foundation

Inspiring ocean awareness by saving the endangered seahorse and sea dragons around the world from extinction through conservation, research, propagation, and education.

Help us save the seahorse and the coral reefs they live in with a tax deductible contribution to the Seahorse Hawaii Foundation. You will be helping to protect and propagate over 25 species of endangered seahorses, sea dragons and friends.

Make A Tax-Deductible Donation Today!

A Different Kind of Farm (Video) »

Ocean Rider Kona Hawaii

Ocean Rider Kona Hawaii
Seahorse Aqua-Farm & Tours

73-4388 Ilikai Place

Kailua Kona, Hawaii 96740

Map & Directions


Contact Ocean Rider

Copyright ©1999-2023
All Rights Reserved | Ocean Rider Inc.

My Online Order Details

Purchase Policy

Site Terms and Conditions