- This topic has 6 replies, 4 voices, and was last updated 17 years, 3 months ago by Pete Giwojna.
October 28, 2006 at 4:57 pm #966dongeddisMember
Last night my black male Sunburst (H. erectus?) was pregnant, and this morning I woke up to find my seahorse tank full of babies! Probably at least 20. All happily swimming around. Very nice.
Alas, I have no special seahorse fry tank, nor special fry food. I was wondering if there is any chance that any of them will survive on their own, just eating live food they find in the tank.
My overall water system is about 250g. The display has a partition for the seahorses that leaves about 60g for them. There\’s tons of live rock and sand. I\’m already supporting a psychadelic mandarin in the main display, and a green spotted mandarin is a tankmate of the seahorses, and both those fish seem to do just fine hunting their own food (and ignoring the frozen food I add to the tank).
The system includes a 40g refugium, with lots of caulerpa and tons of \’pods. I netted seven of the baby seahorses and put them in the refugium, and there are at least eight remaining in the main seahorse tank. (I\’m amazed that they haven\’t been swept down the overflow yet, but they seem to be hanging out near the front glass of the tank.)
So: any advice anyone has for perhaps keeping a couple of these alive? Given that I\’m not going to set up an entirely separate system just to raise fry. Might there be a chance that a couple could survive eating live \’pods in the refugium? Should I feed some (bottled) Kent\’s zooplankton? Or is my quest basically hopeless without a dedicated fry tank + fry food?
— DonOctober 28, 2006 at 6:13 pm #2963nigelseahorseGuest
Sorry to tell you this but those babies you netted out will die. They swallowed air and will die because they will have boyancy problems. I think this batch of babies wont make it they realy need baby brine shrimp to eat. So next time get a nursery tank and some BBS before more babies are born. Thats if you want to raise babies. Please do more research before considering raising babies.October 28, 2006 at 8:31 pm #2964dongeddisGuest
I appreciate your advice, and I have done some research, which is why I’m aware of the use of nursery tanks and baby brine shrimp as the typical solution.
I’ve chosen not to go that route, and it is not a goal of mine to raise baby seahorses. That said, I happen to have some baby seahorses right now, by accident.
I’ll accept your death sentence for the netted babies, although it seems extreme to guarantee that all of them will die.
But my real question is related to how these things survive in the wild. Surely you must know that baby brine shrimp is not a natural seahorse food, as brine shrimp don’t exist in the ocean.
Given that my refugium has plenty of caulerpa (for holdfasts), very mild water current, and tons of copepods and amphipods, I thought there may be a chance that a few of the seahorse ponies will survive eating that live food.
Do you know what they eat in the wild? Might it not be that they survive in my tank exactly the same way that they survive in the wild? I understand that the nursery tank + BBS is the recommended approach to maximize the yield from a brood, but that wasn’t my question. My question is whether there is any chance that at least a couple of them will survive for awhile and find food to eat.October 29, 2006 at 6:41 pm #2973Pete GiwojnaGuest
Yes, sir, Sunbursts are indeed Hippocampus erectus. Congratulations on your new brood of fry!
A refugium teeming with pods is certainly worth a try for anyone who is dealing with a brood of fry and is not set up for rearing but nevertheless wants to give the newborns a chance, however slender that may be. The natural food of seahorse fry in the ocean is zooplankton, and research suggests that the bulk of this consists of larval copepods for many seahorse species.
The sort of simplified rearing system you’re contemplating is usually known as a "natural nursery," as described below, Don:
The Natural Nursery.
This is a very small-scale, low-maintenance rearing system sometimes employed by harried home hobbyists who are too busy for the brutal feeding regimen and maintenance schedule most other nurseries require. Natural nurseries rely on lots of live rock for biofiltration and are usually set up more or less as a refugium would be. That means lots of macroalgae to provide natural filtration and no predators of any sort, which allows thriving populations of copepods, amphipods and other microfauna to build up over time. The idea is that the overworked aquarist can simply cull through his seahorse’s latest brood, release the hardiest of the newborns in the natural nursery, and allow them to fend for themselves. Sometimes a netful of newly hatched brine shrimp is added now and then to supplement the natural microfauna on which the fry survive, but this is done sporadically at best to stave off the appearance of hydroids and Aiptasia anemones that might otherwise rapidly take over the nursery. The natural filtration provided by the live rock and beds of macroalgae reduces the need for water changes to a minimum and feeding is drastically curtailed compared to other types of nurseries.
As you might expect, most of the fry are lost during the first week or two with this method, but some may manage to find enough natural fodder to survive and it’s not uncommon for a few of them to thrive on their own. That’s all the hobbyist is hoping for with this system and such meager survivorship is considered a victory, since the only alternative in many cases is to sacrifice the entire brood without attempting any rearing whatsoever.
This method of rearing is most successful when the natural nursery/refugium is large and the number of fry it is asked to support is small. For instance, Liisa Coit has used a 5-foot seagrass refugium this way quite successfully when rearing dwarf seahorses (Coit, pers. com.). It is best suited for raising benthic seahorse fry but is also worth a try for raising pelagic fry when there is no other alternative. <Close quote>
So attempting to rearing seahorse fry as you describe will result in very high mortalities, but it is far from hopeless, and it is not uncommon for one or two of the fry to hang in there against all odds and find enough natural fodder to grow and prosper. For example, Heather Hall maintained a rearing program for Hippocampus capensis at the London Zoo that was proving to be too successful, prompting a change in their rearing protocol. In order to keep from being overrun with captive-bred capensis, the Zoo was forced to resort to unusual methods to reduce the reproductive rate of their colony. She describes her experience raising these bountiful breeders as follows: "H. capensis is a relatively prolific species. Brood sizes average about 50 babies… Since survival rate is high with good husbandry and diet, it is easy to become overpopulated with animals. In order to avoid overpopulation we have tried different ways of managing the population in our collection. Separating the sexes was employed in several tanks. Sexes were kept isolated in groups of 20. We found that this led to many problems. The animals exhibited a number of stress signs: disease outbreaks increased and aggression was high between males. Females became swollen with eggs and suspected egg binding occurred. Respiration rates and twitching also increased. Therefore, we decided to separate the sexes of our seahorses no longer. Animals in the display tank are allowed to reproduce as normal, and young are only removed when required. Some young survive in the display tank, feeding on naturally available foods and make it to adulthood. To keep the generations turning over, we can remove up to 20 individuals and raise them in the holding tanks. They can be given special attention there and their growth monitored. This method has worked well for us" (Bull and Mitchell, 2002, p30).
In the end, H. capensis fry at the London Zoo were simply left to their own resources in the display tank with their parents, yet some of them routinely survived to adulthood on their own with no special care whatsoever. Those are benthic babies and the situation is a little different with your Sunburst fry, but certainly worth a try, Don.
Now that your Sunbursts have begun breeding for you, they made produce a new breed every month. Nigel is correct when it comes to transferring the fry from your main tank into the refugium, Don. You must be very careful when transferring the babies into your nursery tank. For future reference, never lift the newborns out the water when transferring them. They will swallow air and may 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).
Best of luck raising your Sunburst fry in the refugium, sir! Here’s hoping a few of them managed to thrive.
Pete GiwojnaOctober 29, 2006 at 11:23 pm #2981dongeddisGuest
Thanks so much, Pete. VERY helpful.
Assuming this happens again, I’ll pay more attention to yours (and Nigel’s) advice about not exposing them to air. I had planned (after reading Nigel’s comment) on just using a small cup, but your suggestion of a turkey baster is amusing; I may try that.
Alas, while I saw upwards of 20 babies the first morning, by 24 hours later I can no longer spy a single one. Doesn’t mean they’re all dead, of course. I have tons of live rock and caulerpa, and the little guys are so small that a bunch of them could easily be hiding in places I can’t see. I may need to wait a few weeks and see if any survived to grow large enough to spot.
In any case, thanks so much for the advice. If this is really going to turn into a monthly event, and I find 20+ babies each time, it sure seems like I’ve got a chance of eventually growing a few new youngsters, even without a separate nursery tank.
I guess my final question is whether there is anything simple I could do to improve yield. In particular, what preys on baby seahorses? Like any typical reef tank, mine has bristleworms, hermit crabs, brittle starfish, snails, aiptasia anemones, along with the adult seahorses. I suspect the aiptasia might eat some babies, but I’m already trying to limit them for the sake of the main reef tank, so that doesn’t matter. Are adult seahorses cannibalistic? Is it critical that I remove all the babies into the refugium? It sounds like the London Zoo actually raised them in the display tank, which seems like a surprising success. Might cleanup crew like bristleworms attack a small seahorse?
I’m not sure if there’s much I can do about it in any case. Can’t remove all the bristleworms, even from the refugium. But at least the refugium doesn’t have hermit crabs (dangerous to babies?) or snails (probably doesn’t matter). I’d guess that aiptasia is probably the biggest threat that I might be able to do something about.
Thanks again for all the info.October 30, 2006 at 2:11 am #2982trulyshyGuest
I woke this morning to the same problem you had. At first I thougt it was food swimming in the tank…. I was like, :woohoo: OMG where did all that come from… my water! My water!! I just wanted to start to net the access when I noticed they were babies. I read your post and remember the "air" advice….
I took a small cup and caught the most, the rest I used the turkey baster method. I know I probably have null chance of getting any through, but I thought I’d at least try to give them the best possible chance I could give them and that was down below. I have so much calupra and other algea growing there. Some did slip through and they went on a roller coaster ride through the pump and right back up to the main tank…
Hardly little bastards…. :blink:
I gave up putting them below and thought, you guys are on your own…..
I was surprised, the fish did not eat them at all. I have a maroon clown, damsel fire fish and yellow Gobies. I was sure one of them would go after them. They did go after them but than noticed it wasn’t food and actually left them alone.
I fed the seahorses and sometimes young would swim by, I thought for sure the seahorse would mistake the young for food, buy they were very careful and did not eat their own young.
I hope you have more luck in at least getting one or so through. It would be totally cool if you did.
christineNovember 1, 2006 at 2:31 pm #2991Pete GiwojnaGuest
You’re very welcome, sir!
Yup, once your Sunbursts begin breeding regularly, they will typically produce a new brood for you every month or so. And you can expect the brood size to increase over time as well, so it’s a good idea to implement any measures that may help boost the survival rate of the newborns in your refugium/natural nursery.
Cannibalism ordinarily isn’t a problem at all, so you shouldn’t have any problem whatsoever leaving the parents in with their offspring if need be. But there are indeed a number of other predators you should be aware of that can take a toll on the fry.
For example, aside from their parents, any fish with malls large enough to swallow the newborns are apt to do so. Likewise, decorative shrimp of all kinds — fire shrimp, cleaner shrimp, peppermint shrimp, etc. — will actively prey on seahorse fry and can rapidly decimate a brood. Snails are just fine but crabs of all kinds can pose a risk to the newborns after the fry pass through their pelagic phase and begin to orient to the substrate. Scarlet reef hermit crabs (Paguristes cadenati) and micro-hermit crabs that stay tiny and micro stars (miniature brittle starfish with a leg span no greater than perhaps a dime) are usually okay, but larger hermit crabs and serpent starfish may become opportunistic predators of baby seahorses.
Stinging animals such as hydroids (both the colonial stage and the hydromedusae jellyfish) and anemones will take a heavy toll on the newborns, so you’ll want to eliminate the Aiptasia rock anemones if possible.
Other than that, you just need to make sure that your filters and overflows don’t "eat" any of the newborns. Sunburst fry go through a pelagic or free-swimming planktonic stage and tend to cluster your the surface for the first several days of life, and these surface huggers are vulnerable to overflows and prone to getting filtered out, so beware of that as well.
Best of luck with your natural rearing system, Don! Here’s hoping some of the youngsters managed to thrive when left to their own resources amidst the abundant pod population in your system.
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