You’re very welcome.
It’s difficult to say if there is any cause for concern at this point are not without knowing more about your stallion and his history as a breeder. For instance, 100 offspring would be a large brood of babies for many seahorse species, but for other prolific ponies (e.g., Hippocampus reidi, H. ingens, H. abdominalis) it may be just the tip of the iceberg. So it’s important to know what species of seahorse you have, and it’s also important to know whether this is his first brood or if he is an experienced breeder that has been churning out brood after brood for you over the last several months. First-time breeders and inexperienced males often have inordinately small broods, and if you’re stallion is a Brazilian seahorse (H. reidi), then he may just be getting warmed up and the first 100 newborns may simply be his opening salvo.
Has your pregnant male experience any health problems recently that could cause complications and make this a difficult delivery? Is he having any problems swimming normally as a result of positive buoyancy (i.e., the tendency to float)? If he isn’t having any buoyancy problems, then it’s probably safe to assume that his distended pouch is carrying more undelivered young rather than bloated due to a build up of gas.
Gravid males are always distressed and uncomfortable during labor and there’s not really much you can do to assist your stallion if he’s having a difficult time. About all you can do is provide him with optimum water quality (especially good dissolved oxygen levels), give him nutritious foods to eat, and provide him with a stress-free environment in which to deliver his brood. For example, don’t separate him from his mate or transfer him from his happy home in your main tank into a "paternity tank" of some sort to deliver his young, both of which are very stressful for a pregnant male.
Best of luck with your pregnant stallion and his prolonged labor, makala007! Here’s hoping he delivers the rest of his offspring very soon.