How Do I Know If My Seahorse Is Pregnant?

Seahorses may be called a seahorse, but they are actually a very unique fish.

One of the most unique characteristics of seahorses is that the male is the one that gets pregnant and hatches the eggs.

With this in mind, seahorse owners often ask, how do I know if my seahorse is pregnant?

The easiest way to know is to monitor your seahorses, especially if you are wanting them to mate.

You will know your seahorse is pregnant because the female who is swollen at the midsection with eggs will be suddenly slimmer one day while the male’s pouch will be bloated from being full of the eggs the female has injected into him. You’ll also know because the male’s pouch will remain swollen for more than 3 days.

There is a little more to it than this so let’s dive in and explore…

Insider Tips To Tell If Your Seahorse Is Pregnant

  • Shine a flashlight through the aquarium. If the light hits the seahorse’s pouch, you should be able to tell if it has eggs in it.
  • It may not be that noticeable at first, but it will look like the male swallowed a pea whole.

Other Tell-Tale Signs That Your Seahorse is Pregnant

You should be able to tell fairly easily from your male seahorse’s swollen pouch or mid-section but fi for some reason you can’t tell there are other signs.

You will certainly notice the mating dance the seahorses do every day with the synchronized swimming, so if this suddenly stops and your male seahorse seems immobile or doesn’t eat for a day or so then he is pregnant.

Once the male has the eggs in his pouch he is not a party animal anymore. He is now using a lot of energy to stimulate and feed the eggs so he is not going to be doing much else.

If the male is pregnant then the two parents will continue to interact but not in the same manic disco dance they were involved in before. The female will pretty much just come to find the male each day to hang out with him and let him know she is there.

Apparently, they will still dance together but more like a slow dance to a country song rather than the cha-cha. Before the male would draw water into his pouch to puff it up and then blow it out to show off for the female but now he is tired and wondering what he got himself into. They will however continue to brighten their colors when they are together.

If it is the male’s first pregnancy, oftentimes, he will not catch all of the babies in his pouch, so it may be hard to notice if he is actually pregnant, but his pouch will usually darken due to the fertilization and feeding of the eggs inside.

If the male does catch all of the babies, it is almost certain you will notice he is pregnant eventually from the baby seahorses growing within, which will gradually enlarge his pouch even more. Sometimes the male seahorse can carry over 1500 babies inside so his pouch will be especially more noticeable than usual.

If you still fail to notice your male seahorse is pregnant, you may catch on before he is about to give birth because he will show signs of stress from increased heart rate, more respiration, and the babies inside sometimes can be seen moving about right before they are about to be released into their new life, usually early in the morning when it is still dark.

What To Do If Your Seahorse is Pregnant

  • You need to get a nursery tank as soon as possible, with a heater, the proper solution of conditioned saltwater, and some baby brine shrimp ready to feed to the babies.
  • Keep the tank bare-bottom for easier cleaning and get some fake plants so the baby seahorses have something to hitch their tales to.
  • You don’t have to have a filter because you will be vacuuming the tank daily and doing water changes to keep the water clean, but a filter never hurts. If you do get a filter make sure it is a sponge filter or the intake is covered by a screen, and the water flow is either adjustable or very low flow. You don’t want the baby seahorses getting sucked into the filter.
  • When the babies are born, you will have to move them into the nursery tank right away. Just use a light at the surface which will attract them together and scoop them with a cup, don’t use a net because you could hurt them.

How Seahorses Get Pregnant and How it Will Help You Know If Your Seahorse Is Pregnant.

Most seahorses live alone, but if a seahorse is going to get pregnant in your aquarium then you must have a male and female in your tank so you will get to know them and you will recognize when the whole mating process begins. I’ll give you a brief description, so you know what to watch out for.

When the couple is interested in each other, they will begin what is called dancing and swimming together to synchronize their movements so when they exchange the eggs, the male receives them all rather than missing some, which happens a lot with younger seahorses.

When they are ready, they begin swimming toward the surface, and the female uses a tube called an ovipositor to inject the eggs into the pouch of the male.

After the male receives the eggs, he will become a recluse, not eating as much and not doing much because he will be using extra energy to fertilize the eggs and develop them until they are born.

His pouch usually looks like he swallowed a pea and becomes darker.

The female will still come to visit him every day but they will just mingle a little rather than their synchronized swimming.

If you witness part or most of this process, you should be able to at least suspect your seahorse is pregnant.


Again, if you missed the female actually injecting her eggs into the pouch of the male then here are some things to watch for:

  • The male becomes a recluse and right before birth he is stressed out with more respiration and swimming back and forth like a nervous mom about to give birth.
  • The seahorse couple will still dance a little, but without the synchronized swimming and all the twitter-painted fireworks.
  • The female is suddenly much slimmer, like two months of Jenny Craig packed into one day and the male’s pouch is noticeably darker.

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