Re:over-due dad?

Dear Donna:

The newly hatched brine shrimp (1st instar Artemia nauplii) certainly are pretty small and it can be difficult to see them being slurped up, but you should be able to see the fry tracking and snicking at the live food. If you are not able to tell conclusively that they are eating just from watching the fry’s behavior, then checking their fecal pellets is another good way to tell if they are eating enough, or perhaps are even getting too much to eat.

When the fry are well fed and eating well, defecation is amazingly rapid, with each newborn producing an average of one fecal pellet every 25-30 minutes. So watch the fry to make sure they are eliminating regularly and check the bottom of the tank for numerous fecal pellets. (You’ll want to vacuum up any fecal pellets from the bottom when you make the water changes in the nursery tank.) If the newborns are not producing regular feces, or there is only a light defecation occurring, then they may not be eating or may simply not be getting enough to eat.

Many breeders will examine the fry’s fecal pellets under a microscope to determine how well they are digesting the baby brine shrimp. If the fry are eating too much too quickly, deification is so accelerated that the newborns cannot adequately digest the hard bodied Artemia nauplii before it’s a lemonade, so they will actually begin passing living brine shrimp in their feces. But most home hobbyists have a hard time keeping up with the endless appetites of the fry, and underfeeding is the primary concern for home breeders.

Mustang and Sunburst (Hippocampus erectus) babies should have a hitching post of some sort available to them from day one. The newborns are phototactic and will be attracted to the light, hugging the surface by day, but will often begin seeking out hitching posts after dark straightaway. 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.

As for filtration, sponge or foam filters generally work well for the type of nursery tank as you describe, Donna. 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. If denied access to the surface to inflate their swim bladders, 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 2
http://www.drsfostersmith.com/product/prod_Display.cfm?siteid=6&pCatId=3936

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. For instance, for a 10-gallon tank, I’d suggest using two well-established foam filters, one at either end of the tank for the biofiltration, just as you are planning, Alex.

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.

When weaning the youngsters off of live brine shrimp onto frozen food, it’s still important to make daily water changes and siphon off the bottom of the tanks to clean up leftovers when you do so, since much of the frozen food will go unbeaten at first and you don’t want it to begin to breakdown, incourage bacterial growth, and degrade your water quality. Here are some additional tips for training the youngsters to take frozen food when the time comes, Donna:

Making the Transition to Frozen Foods:
Converting the Fry 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 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.

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 post from Patti that describes how she weaned her erectus fry onto frozen to Kari 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
Director
The Seahorse Trust
36 Greatwood Terrace
Topsham
Devon
England
EX3 0EB

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.

Once the juveniles reach the age of about six months, they will be hitting sexual maturity and should be ready to transfer into the main tank with regular filtration, protein skimmers, etc.

Best of luck with your first attempt at rearing, Donna! Here’s hoping all goes well and that you are able to raise some of the young to maturity.

Happy Trails!
Pete Giwojna