preparing for the arrival of first batch of fry

Dear 67:

Congratulations on your upcoming brood of babies!

If you have a good idea as to when the successful mating took place, you’ll be able to estimate the delivery date and, if possible, you should try to be present for the big moment so you can witness the spectacle in person.

No matter how often I see a male giving birth, it never ceases to amaze me. Watching the fry erupt into existence that way is an incredible sight. They are perfect miniature replicas of their parents, able to fend for themselves from the first. It seems a brutal beginning, a ruthlessly rude awakening, to be violently thrust into the world in such an abrupt fashion, but the newborns hit the water swimming without missing a stroke. It’s a thrill to be witnessing such a miracle of nature and always leaves me awed and exhilarated!

If you want to catch the big event, this is what Carol Cozzi-Schmarr at Ocean Rider recommends in that regard:

“In my experience, I have seen that 90% of the time the male seahorse will give birth right at the crack of dawn. For example, in one section of our hatchery we have over 50 pairs of seahorses. On any given morning if you show up just before dawn, you will witness at least 5 males giving birth at exactly the same time which is right at dawn. It is spectacular!! So, I would bet that if you set your alarm to 1 hour before sunrise you just might get lucky!! But of course, you will have to ask Mr. seahorse to be sure!!!”
Aloha, Carol

In the meantime, 67, whether to allow the pregnant male to give birth in the main tank and then to transfer the fry to the waiting nursery, or to transfer the expectant father to the nursery tank ahead of time so he can delivery his brood there is a very important decision for you to make, but if you think about it, it will be obvious what to do. There are two schools of thought on this issue. Some hobbyists feel it’s best to use the nursery tank as a paternity ward, since the delicate newborns never need to be handled if the male gives birth directly in the nursery. Other breeders feel it’s better to disturb the pregnant male as little as possible and prefer to have him deliver his brood right where he is, in the familiar surroundings in which he’s most comfortable.

That’s a no-brainer, folks. In my opinion, it’s ALWAYS better to assure the well-being of the male and safeguard your broodstock. A pair-bonded couple will soon establish a regular breeding cycle in the aquarium, producing a new brood every two, four, or six weeks. (The gestation period varies with the species and is often correlated with the lunar cycle so that the fry are delivered during the highest tides, which helps disperse the young in the wild; Vincent, 1990.) A healthy pair-bonded male will deliver a new brood of young every month or so during the breeding season, producing countless offspring over the course of its life. But if you lose a breeding male, you lose all of his future progeny with him, as well as the superior genetic traits he carries. It is folly to jeopardize the health of a pregnant male for the sake of the brood he is carrying at the moment.

Handling a gravid male, especially when the pregnancy is well advanced, should be avoided at all costs. At best, it will be stressful for the male to be captured, separated from its mate, and transferred to a strange new environment (Giwojna and Cozzi-Schmarr, Feb. 2002). At worst, rough handling and stress can trigger premature delivery or cause the pregnancy to be aborted altogether, adversely affecting the health of the male and his brood (Giwojna and Cozzi-Schmarr, Feb. 2002). Stressing a pregnant seahorse has many detrimental effects, including decreased appetite, adverse hormonal changes, impairing the immune response and lowering disease resistance.

Separating the expectant father from his mate at this crucial time can also prevent him from re-mating with his chosen partner and may even break up a pair-bonded couple (Giwojna and Cozzi-Schmarr, Feb. 2002). Throughout his pregnancy, the male maintains daily greeting rituals with his mate that serve to strengthen and reinforce their pair bonds and keep them physiologically attuned to one another. When the male gives birth, his mate is normally waiting nearby, ready to hydrate her clutch and rise for the exchange of eggs as soon as he has recovered. Many times they will resume their mating dance and re-mate moments after the male delivers his latest brood.

Isolating the male from his partner during the pregnancy effectively puts an end to all of that. They are preventing from conducting morning greetings, their carefully orchestrated breeding cycle may be disrupted as their hormonally regulated reproductive synchrony is lost, and the pair bond is weakened accordingly (Giwojna and Cozzi-Schmarr, Feb. 2002). Their bonding may even be broken as a result. That’s not what a successful home breeder should strive for!

If you are concerned about the filtration in your main tank “eating” the newborns, modifying your filter to prevent this is a much better alternative than transferring the male to a paternity ward (Giwojna, Feb. 2002). Just screen off the intakes or cover them with sponge prefilters. Or you can simply switch off the skimmer and any supplemental powerhead(s) when his due date arrives and delivery is imminent. (Just don’t shut down your primary biofilter!) That way, the male can remain with his partner through the pregnancy and deliver his brood in a stress-free environment.

Here are Carol’s thoughts on the matter:

“As Pete mentioned, probably the most stressful thing one could do to a pregnant (gravid) male that is close to giving birth would be to “handle” him by moving the male from his normal environment (home!!) to a new and unfamiliar environment like a different holding tank. (hotel room!!). This unnecessary “transfer” and ” handling” will force him to adapt to a strange environment causing a general increase in his stress level causing many possible negative outcomes such as decrease in appetite, lowering of the immune system causing opportunistic pathogens currently present in the aquarium but not at high levels to take a hold on the sea horse causing health problems, and sadly may prevent him from re mating with his mate.

You see, the male will continue his bonding rituals (such as Pete has described) with his mate during the birthing process and immediately after giving birth. The pair will begin the treasured mating dance that will hopefully result in a successful egg transfer from the female to the male often within hours after giving birth!! Remember that with many sea horse types the older the male the larger the size of his pouch and therefore the greater the number of sea horse babies in the pouch!! For example, a 5 year old adult H.reidi male may give birth to as many as 2000 babies with each spawn!!!! A young 6 month old juvenile male may only give birth to 10 or 20 babies!!! It is also more likely that the older male has been mating with the same female all is life!! Imagine the stress of not being with his ” beloved” during this time!

This unnecessary “handling” or “transfer” is, of course, extremely hard on wild caught males and may cause his death immediately after giving birth. One should avoid purchasing wild caught pregnant males at all costs. It is easy to feel sorry for him in the pet store, but his purchase only encourages the collectors to take additional pregnant males the next time causing further devastation to the already highly threatened wild sea horse populations.

Certainly this “handling” or “transfer” stress is greatly reduced with the farm raised pregnant males but the general concept still applies. If you purchase a farm raised pregnant male you should not expect a male that is almost ready to give birth but one that is within 2 weeks of giving birth. The normal gestation period averages at 30 days depending mostly on species and environmental parameters such as temperature and diet.

If these conditions are not optimum and the general stress level of the male is too high, the male will simply re-absorb the eggs or abort them. You will sadly think that he was never pregnant

If, however, you are able to keep these parameters optimum, you will have a much greater chance of being successful with your pregnant male so that you can enjoy this amazing phenomena of the pregnant male sea horse!! With a little more patience you will surely be rewarded with the great performance of the sea horse mating dance followed by the most precious site of all……the fat bellied pregnant male sea horse!!!”

Aloha, Carol Cozzi-Schmar

Generally, the only time I feel a paternity tank is advisable is on those rare occasions when a pregnant male develops a health problem that requires treatment (Giwojna, Feb. 2002). In that case, it’s best to make the transfer early in his pregnancy (at least 2 weeks prior to his delivery date). Make sure the hospital tank/paternity ward has been prefilled with water from the main tank to reduce stress and ease the transition. If at all possible, transfer his mate along with him. And situate the paternity tank in a quiet, low traffic area, making certain it includes enough shelter so that the expectant father won’t feel vulnerable and exposed.

in this case, 67, you are fortunate to have plenty of time to prepare for the big event. Here’s what I’d recommend under the circumstances:

First of all, you’ll need to carefully transfer the newborns from the main tank into a makeshift nursery tank (I’ll explain how to set up a simple nursery tank later in this post). Remember, you must be very careful when transferring the babies into your nursery tank. NEVER lift the newborns out the water when transferring them. They may swallow air and develop fatal buoyancy problems that leave them bobbing helplessly at the surface, unable to submerge or eat (Giwojna, Jan. 1997). Netting them out or otherwise exposing the newborns to the air is one of the most common mistakes inexperienced breeders make, and it often results in the loss of the entire brood (Giwojna, Jan. 1997). The proper way to move the babies is to carefully scoop them up in a small cup or bowl, and gently immerse the cup in the nursery tank to release the fry (Giwojna, Jan. 1997). Or a common turkey baster works well for gently sucking up one or two of the fry at a time along with a little water, and then releasing them into their nursery (Giwojna, Jan. 1997).

Secondly, you’ll need to fire up a battery of brine shrimp hatcheries 24-48 hours in advance of the gravid male’s due date, so that you can provide the newborns with plenty of newly hatched Artemia nauplii as their first food, as soon as possible.

Here is some information on how to set up a simple nursery for the newborns, 67:

Basic Nursery Tank

The simplest nursery tank setup is a bare bottom 5 to 10-gallon glass tank equipped with suitable hitching posts, an air-operated sponge or foam filter, and nothing else (Giwojna, Jan. 1997). Add a cartridge of activated carbon to the airlift tube of the sponge filter(s) to provide a little chemical filtration.

Keep the sponge filters in such nurseries elevated or prop them up off of the bottom. Otherwise they can become death traps for unwary benthic fry, which can become wedged beneath them and trapped. Adjust the airflow through the sponge so it produces a stream of small, steady bubbles. You want to create a slow, gentle flow through the foam filter without generating overly fine or excessively large bubbles (Giwojna, Jan. 1997). Seahorse fry may accidentally ingest fine bubbles, mistaking them for food, while large bubbles can buffet the newborns with harmful results (Giwojna, Jan. 1997). Too much airflow through the sponge filters will leave them prone to “eating” the fry’s food (newly hatched Artemia, copepods, rotifers, etc.).

At the same time, however, you want the air stream to break up surface tension and provide adequate surface agitation. This is important not only for efficient oxygenation and gas exchange at the air/water interface, but also to allow the fry easy access to the surface. A newborn’s first instinct is to head to the surface to fill its swim bladder. (Physosymotous fishes have a connection between their gas bladder and the gut in the form of an open tube called the pneumatic duct, and are thus able to fill the swim bladder by gulping air at the surface. Like many teleost fishes, seahorses lose this connection very early in life, so that their swim bladders are completed closed as adults.) In many species, gulping air is the way in which gas is first introduced into the larvae’s bladder, and if denied an opportunity to do so, their development is hampered due to uninflated swim bladders (Silveira, 2000).

This is the case with seahorse fry of most species. If denied access to the surface to inflate their swim bladders initially, the fry behave normally while they are small and their weight is still negligible. But over the weeks, as they grow and put on weight, their underdeveloped swim bladders and inability to achieve neutral buoyancy increasingly handicap them. Once they gain a little weight, they sink like rocks. Unable to swim, they are reduced to slithering along the bottom on their bellies and are commonly referred to as sliders. This deficiency does not become apparent until the fry are several weeks old. Needless to say, this hinders their swimming ability and severely limits their feeding opportunities, delaying their growth and development, and rendering entire broods useless. In several cases, the problem was traced back to an oily film on the surface of the nursery tank, which prevented the newborns from filling their swim bladders with air (Silveira, 2000). A protein skimmer will prevent this by removing filmy surface layers and surfactants in general.

The same sort of sponge filters that work well for dwarf seahorse tanks are also ideal for nursery tanks. Be sure to avoid sponge filters with weighted bottoms or other metal components since they will rust when exposed to saltwater. Sooner or later this will cause problems in a marine aquarium (sooner in the small nursery tanks). Select a sponge filter that has no metal parts and is safe for use in saltwater. The proper units will have suction cups to anchor them in place rather than a weighted bottom.

The sponge filters I find that work well are the Oxygen Plus Bio-Filters (models 2, 3, 4, or 5) or the Tetra Brilliant foam filters. They have no metal components, making them completely safe for use in saltwater, and just one of these foam filters will do the job on a tank of 5 gallons or less. They do not have a weighted bottom but are equipped with suction cups instead.

Click here: Foam Aquarium Filters: Oxygen Plus Bio-Filter
http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=3954

Avoid the Oxygen Plus Bio-filter 6, 11, and the Multi sponge, which all have a weighted bottom (metal), that rusts when exposed to saltwater. If you want more filtration, you’re better off going with two of the smaller suction cup sponge filters rather than any of the models with weighted bottoms.

All you need to operate sponge or foam filters is an inexpensive, diaphragm-operated air pump (whatever is available at a reasonable price from your LFS will do just fine), a length of airline tubing to connect the air pump to the foam filter(s), and a set of air valves (gang valves) to regulate the air flow to the filters. That’s all — nothing to it! The inexpensive Apollo 5 air pumps work great for sponge filters, but whatever air pump you have on hand should certainly do the job.

Cleaning the foam filters is a snap. Simply immerse them in a bucket of saltwater and gently squeeze out the sponge until it’s clean and releases no more sediment or debris. (I use the saltwater I siphoned out of my aquarium when performing a water change for this, and clean my sponge filters whenever I change water.) Run a bottlebrush through the inside of the tube, wipe off the outside of the tube, and you’re done. The filter is ready to go back in the aquarium with no impairment at all of the biofiltration. Takes only a couple minutes.

Setting Up & Maintaining the Nursery.

The nursery tank(s) should be filled with water taken from the main tank that houses their parents, so the delicate newborns can be transferred directly to the nursery without adjusting to any stressful changes in pH, temperature or salinity (Giwojna, Jan. 1997). 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. 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.

If you can obtain the fine-bladed or feathery varieties, live Caulerpa will help maintain good water quality by removing excess nitrates, as well as providing natural hitching posts that help benthic seahorse fry feel right at home (Giwojna, Jan. 1997). These marine plants grow from woody holdfasts and don’t need to be anchored in a sand or gravel substrate, so they’ll do fine in a bare-bottomed nursery (Giwojna, Jan. 1997). However, live Caulerpa is more difficult to keep clean and sanitary, and for this reason, many breeders prefer artificial hitching posts for their nurseries such as those described above (Mai 2004b).

In addition, hydroids and miniature jellyfish (the free-swimming hydromedusae stage of the hydroids) are often present on live marine plants, and they can easily be accidentally introduced to the aquarium along with the Caulerpa. Ordinarily, this is not a problem for the greater seahorses, but hydrozoans can wreak havoc when they become established in a nursery tank. Not only will they compete with the fry for food, their stings can be lethal to the babies or leave them susceptible to secondary infections (Vincent, 1995c), and hydroids are sometimes responsible for mass mortalities in nurseries.

A brief quarantine period for Caulerpa and other marine plants, during which they can be treated with fenbendazole granules for several days, is therefore a good precaution. Fenbendazole is an inexpensive deworming agent used for hoses and other large animals, and treating the quarantine tank with 1/8 teaspoon per 10 gallons is guaranteed to eradicate hydroids before they can gain a foothold in your nursery tank (Liisa Coit, pers. com.).

Good lighting is also essential for the nursery tanks. The fry must be able to see the tiny organisms they live on clearly in order to feed efficiently. Use ”Daylight” fluorescent tubes or the equivalent and leave them on for a minimum of 14-17 hours a day, since the fry need to eat for at least 14 hours everyday (Vincent, 1995c).

Since the nursery tanks have limited filtration, daily water changes are typically needed in most systems to maintain water quality and keep up with the metabolic wastes and oxygen demands of several dozen baby sea horses and the thousands of brine shrimp needed to feed them (Giwojna, Jan. 1997). When the fry are well fed, defecation is amazingly rapid, with each newborn producing an average of one fecal pellet every 25-30 minutes (Herald and Rakowicz, 1951). The best way to perform the necessary maintenance is to use a length of airline tubing to siphon off the bottom of the nursery tanks a minimum of twice a day (morning and evening are ideal for this; Giwojna, Jan. 1997). Replace the water that was removed while siphoning with freshly mixed saltwater that has been pre-adjusted to the same temperature, pH and salinity as the rearing tank. Change about 10-20% of the water each time you siphon the bottom, so that a total of at least 25-50% of the water in the nursery tanks is exchanged every day (Giwojna, Jan. 1997).

Blacking out the top 2/3 of the aquarium and using side lighting or bottom lighting are techniques that are often used to help keep pelagic seahorse fry away from the surface, but there are many other (and better) nursery tank designs such as kriesels/pseudokreisels and in-tank nurseries that are more efficient at preventing surface huggers and floaters, so referred to Lesson 8 (Rearing the Young) in the seahorse training course for more suggestions along those lines.

For starters, here are some tips on hatching and enriching the baby brine shrimp you’ll need to feed the newborns, 67:

Hatching Out Brine Shrimp (Artemia)

Many commercially made hatcheries are available or you can easily improvise your own from 2-liter soda pop bottles or quart jars. Fill the jars or bottles about 4/5 full with saltwater or brine solution and equip each container with an airstone connected to a length of rigid airline tubing that reaches all the way to the bottom. An inexpensive vibrator air pump with a set of gang valves with put out enough air for the entire battery of hatching containers. Add 1/8-1/4 teaspoon of brine shrimp eggs to each container and adjust the valves so the airstones bubble vigorously, keeping the eggs in suspension at all times. Shine a light directly on the hatching bottles and keep them illuminated 24 hours a day. A temperature of 80-82 degrees F is optimum for hatching brine shrimp.

The eggs will begin hatching after 1-24 hours, and the emerging nauplii should be harvested and used as soon as possible after incubation while they still retain their full nutritional value. (The yolk supply lasts about 6-8 hours after hatching, and the food value of the nauplii deteriorates steadily as the yolk sac is consumed. Once it has been exhausted after about 8 hours, the nutritional worth of the nauplii drops drastically.)

However, before they can be used as food, the nauplii must first be separated from the indigestible egg shells. Otherwise the empty shells may be accidentally ingested by the seahorse fry, which has been known to cause intestinal blockages and death.

The brine shrimp nauplii can be separated from the eggs simply by turning off the air for a few minutes and allowing the water to settle. The unhatched eggs will sink to the bottom of the hatching jar while the empty egg shells will float to the top. The nauplii can then be concentrated in the center of the jar by darkening the room and shining a flashlight on the jar’s midsection. (Brine shrimp are attracted to light and will be drawn together in midwater where the light is focused.) Harvest the nauplii by using a siphon or turkey baster to suck up the concentrated mass of shrimp. The shrimp-laden water can then be strained through a plankton screen or fine-meshed brine shrimp net.

Return the strained water to the hatching container, add more eggs, and readjust the aeration. The same hatching solution can be used for a week’s worth of hatchings before it has to be replaced.

Alternating the hatching container from which you harvest each day’s supply of nauplii will assure that you have a nonstop supply of newly hatched brine shrimp available at all times.

If you’re still uncertain about how to proceed, the information at the following link should make everything perfectly clear:

Click here: Brine Shrimp Technical Information 1
http://www.brineshrimpdirect.com/brineshrimpdirect-faq-1-2-13.html#hatching

Okay, 67, those are some tips to get you started off on the right foot. When it comes to setting up and cycling a nursery tank, I always avoid live sand and live rock and use a bare bottom tank instead because it is so much easier to keep clean and sanitary, siphoning off the bare bottom when you perform the daily water changes. The air-operated sponge or foam filters can be cycled quickly and easily simply by adding SeaChem Stability to the nursery tank for seven consecutive days.

Finally, if you send me a brief e-mail, I can provide you with a lot more detailed information on rearing the young and different nursery tank options, as well as recommended feeding schedules, etc.

You can always reach me at the following e-mail address:

[email protected]

Best of luck raising the offspring when the time comes, 67!

Respectfully,
Pete Giwojna, Ocean Rider Tech Support