Help! My Seahorse Just Had Babies!
Or, what to expect when you didn’t know you were expecting.
You just walked by your tank to discover dozens, if not hundreds of tiny seahorses drifting around your aquarium. These miniature copies of the adults caught you off guard, and now you’re not sure what to do. This guide will walk you through what you need to do within the first few hours to try and save the young seahorses.
In the immortal words of Douglas Adams; Don’t Panic!
The absolute first thing you must do is decide if you really want to try to raise these babies. Raising baby seahorses is a time, space, and money consuming task. And there is no guarantee that you’ll be successful; very few seahorse fry survive in the wild. Being unprepared means that you’ll be starting from a disadvantage as well. However, thanks to their yolk sack when born, baby seahorses can go 24 – 48 hours without food so you have a bit of time to sort out obtaining the appropriate food. (Be aware, the longer you wait, the more perilous it gets for the young even with that first 48 hours.)
Okay! So you’ve decided that you do want to take on the challenge. Now what do you do? The first thing you’ll want to do is turn off any filters or pumps that could harm the babies. If you have an air pump, leave that running or add one to the tank so that there is some oxygen exchange while the main pumps are off.
You’ll need to start looking at what equipment will be needed to get the fry through the first few days, and how much of that equipment that you may already have. Removing the fry from the tank as quickly as possible is your best chance for success, so at a minimum you’ll want some kind of container to house the babies. Any moderately sized container should work as long as it hasn’t been previously used with any kind of chemicals. A bucket, gallon pickle jar, spare 10 gallon hospital tank (. . . you do have that, right?). A container around a gallon or larger is ideal in a pinch. A breeder net would also work as a temporary solution.
One you have a container to act as the nursery, fill the container with water from the parents’ tank. Try to keep the newborn seahorses off the surface of the water. This is best achieved with an air pump. If you don’t have one on hand, place the light at the bottom of the container and cover the top with something dark to help keep the babies from swimming to the top where it’s normally brightest. Seahorse fry are attracted to light so you can use this to your advantage.
If at all possible, don’t use a net to collect the fry. Exposure to air can cause problems. Additionally, many have small spines that, while barely visible, can get stuck on the net. It’s best to use a cup to scoop them out, or a clean turkey baster to suck them up. Their natural attraction to light can help collect them. If you turn off the main aquarium light and set a flashlight pointed at the side of the tank, the fry will collect there. One thing to keep in mind is that some males take a few days to deliver all their fry. Keep checking the display tank to make sure you don’t miss any. This is especially important if you only find a few initially – they may be “warning babies” – a few that were born a day or two in advance of the entire brood.
Once you have them collected, it’s time to get the shopping list together. The short list of what you’ll need is food, rearing container to act as a nursery, and air pump. Depending on what you already have will depend on what you need to get. If you have a large enough container (2-10 gallons) then you can probably use what you have. Smaller will mean more water changes.
The shopping list will look something like this:
- Brine Shrimp Eggs
- Marine Salt
- 2 air pumps
- airline gang valve/control kit
- ridge air tubing, or weights for airline
- 10 gallon aquarium
- 2 2liter soda bottles.
- Coffee Filters
This is where the real challenge comes in; baby seahorses must be fed live food. What type of food you need will depend on what species of seahorse the parents are.Some are able to eat newly hatched brine shrimp, which you can obtain eggs for at most fish stores and hatch yourself. Other species require much smaller food which is unfortunately more difficult to obtain on short notice.
Here is a list of common species and the foods they can take a birth:
Newly Hatched Brine Shrimp
- Lined Seahorse – H. erectus
- Tigertail Seahorse – H. comes (there is some debate on this, I think they’re right at the size that they struggle with it, but in a pinch, I’d definitely try baby brine shrimp.)
- White’s Seahorse – H. whitei
- Potbelly Seahorse – H. abdominalis
- Barbour’s Seahorse – H.barbouri
Copepods or Rotifers
- Common Seahorse – H. kuda
- Brazilian Seahorse – H. reidi
- Pacific Giant Seahorse – H. ingens
More information and species can be found in this article on first foods for syngnathids.
If newly hatched brine shrimp are a viable option, obtain the eggs from a local fish store. You’ll also need fresh saltwater, light, an air pump, and a container between 1 and 2 liters.
Hatching brine shrimp is easy, follow the instructions here. You will want to get the brine shrimp started as soon as you have the necessary supplies as it takes 18-24 hours for the eggs to hatch. Newly hatched brine shrimp needs to be rinsed before being fed out. Any brine shrimp not used right away should be refrigerated to keep the
If you have one of the species that requires smaller food, you may be out of luck. Not many fish stores carry copepods or rotifers, and those that do only generally carry starter cultures which will be too few to feed out, and are usually the wrong species for rearing seahorses. However, don’t lose hope! Try your local fish clubs, you might find a nearby member who raises them. You can also get large quantities shipped overnight from a number of different vendors. Check out our list of live food suppliers.
Enriching baby brine shrimp and rotifers is very important for overall growth and health of fry, which you can read about here. For the scope of this article, we are focusing on the most urgent issue; getting them eating as soon as possible.
Note: there are a few products sold at fish stores that are non-living brine shrimp or rotifers. Seahorses are hardwired to only eat live food, and will not strike at non-living food as babies. If you see any products that you are unsure about, check with the store to verify they are alive. In general foods labeled “instant” will not be alive. Don’t let anyone talk you into trying them – they work for some species of fish, especially freshwater fry. I’ve heard of stores recommending these products based on their utility for freshwater fish, but without the jerky movement of live food, young seahorses just won’t recognize it as something they can eat.
For a container to raise them in, there are plenty of options, but the easiest in an emergency is going to be a 5 or 10 gallon aquarium. You’ll want to have an air pump, but no airstones, to keep the water circulating. Ideally, you’ll want to keep them off the surface – there is a lot of dispute whether or not they will swallow air at the surface, but generally it’s safest to keep them away by using gently rolling bubbles.
Set up the nursery aquarium so that there are a few airlines in the aquarium; in the corners is best. You’ll want a nice rolling but slow bubble. If you have a light, Place it on the side or at the bottom – so the babies swim that direction. A lamp is not necessary, as long as the ambient light in the room is bright enough. Having one on the tank though does make it easier to view the fry, as well as direct where they swim.
If you have one of the hitching fry species, you’ll probably want to add a plastic plant for them to grab on to. Other hitching post options for babies are colored zip ties, nylon string, plastic craft string. Anything small and inert in saltwater will work. However, it’s important to make sure whatever you use does not have small holes that can trap the young. Seahorse fry are weak at this young age and may get tangled in small spaces. Non-hitching species usually start looking for a place to hitch around 2 weeks of age.
You’ll need to feed the seahorses every few hours, and only a moderate You want the seahorse to eat as much as you’ve put in the tank by the next feeding so as to keep the food as nutritious as possible, but not so little that they consume it all right away. You also want to make sure the culture is dense enough that the seahorses don’t have to travel far for food. So if you have a particularly small brood, you may need to feed more and clean out the excess food between feedings.
The ideal amount of food is 10-20 baby brine shrimp per milliliter. Determining this is very easy; remove one milliliter of water, and count the number of baby brine shrimp. This may require a magnifying glass or jeweler’s loop to really get a close enough view to count the shrimp.
Adding live phytoplankton to the aquarium is thought to help with both the feeding response of seahorse fry and keeping food enriched for longer. It also can help with lowering the nitrogenous waste. Some people use it, some don’t. Opinions vary on its value, but if you do use phytoplankton directly in the tank, make sure it is a live, single species inoculant. Multiple types of phytoplankton engage in interspecies warfare using toxins, which you don’t want in a fry tank.
You’ll want to keep the nursery tank as clean as possible; seahorse fry are very sensitive to bacterial problems that can occur in a dirty aquarium. Vacuuming the tank bottom daily is extremely important for removing old food and detritus, which can cause a buildup of bacteria. The surface of the nursery tank should also be wiped down every few days to make sure that any biofilm and algae growing on it is removed. If you don’t have any filtration, then a 100% water change followed by wiping down the tank interior every few days is a good idea.
Water quality is also extremely important. With no filtration, plan on doing at least a 50% daily water change. Keep an eye on ammonia and nitrite levels. Ideally they should be 0ppm, but that can be a difficult goal to obtain in a nursery aquarium with thousands of food items eaten per day by each fry. Dan Underwood of Seahorse Source has observed that they can tolerate ammonia up to 0.5ppm and nitrite of 2ppm without adverse effects. However, keeping it as close to 0 as possible is ideal, so you have some wiggle room if something goes wrong.
An ammonia binding product such as Seachem Prime ® can help in a pinch with excessive ammonia. Ph must be monitored when using an ammonia binder, as it can drop dangerously low. Testing water with an ammonia binder is also tricky; some test kits work with them, and some do not. It varies based on the binder used; be sure to research the products you are using before trusting the test kits’ results.
At between 6 and 8 weeks of age, you can start adding adult brine shrimp and chopped mysis. Adult brine shrimp should be enriched with a high lipid food such as algamac-3050 or Dan’s Feed. Don’t stop feeding baby brine shrimp to the juvenile seahorses until you are certain that they have successfully made the switch to adult brine shrimp. The addition of mysis makes for an even dirtier aquarium and may require multiple daily bottom cleanings. Seahorses can be slow to take frozen mysis, but just keep adding it, and once you see them start to take the mysis, try and encourage the switch to mysis by feeding the mysis first, then adult brine shrimp later in the day.
As the seahorses begin to eat frozen food, they will start to grow faster, but there will also be a lot of uneaten food on the bottom of the tank which will require even more maintenance. The nursery should be vacuumed at least once a day, possibly more. You might want to start thinking about a larger tank depending on the number of survivors. Just be careful, before you know it, you could be dealing with dozens of hungry seahorses!
If you’ve read this far and decided it sounds like more work that you’re willing to take on, you may be able to send the fry off to be fostered. If there is a local breeder, they may have the room and setup to raise extra seahorses. If you don’t know of any breeders, contact your local clubs and fish stores, they may know of someone that has the resources to raise them. Seahorse fry can even be shipped overnight if done within the first day after birth; also check various seahorse and reef message boards for anyone willing to foster the young, or post to the Breeding Forum.
And always remember, in the wild survival for seahorse fry is abysmally low so any success is great! If you don’t succeed the first time, seahorses are a randy bunch, and next time you will be more prepared. And if you decide you are not ready and the thought of raising seahorses is more work than you can handle, don’t feel bad about letting nature take its course.