Rats, I’m sorry to hear that your lonely female is still something of an outcast and is receiving more than her share of grief from your dominant male(s). As we’ve discussed before, that’s a very unusual situation. Captive-bred seahorses are raised at far greater population densities than wild seahorses ever experience, and they are normally quite gregarious as a result. They are accustomed to being around other seahorses and ordinarily appreciate one another’s company very much.
In the aquarium, seahorses do often work out a dominance hierarchy of sorts within the herd, but it’s quite rare for the alpha male to systematically persecute his herdmates, especially an eligible female. When a male displays aggression, it’s almost always directed toward a rival male. As a rule, the stallions do everything in their power to attract the attention of the females, so it is very unusual for the dominant male to be running off a mare like that.
If you’re alpha male is monopolizing the feeding station and driving away the female, her lack of appetite could be stress related. She may simply be so traumatized by the bullying that she is reluctant to come out and feed at all under the circumstances.
It’s an encouraging sign that her girth is good and that her abdomen is still filled out rather than becoming pinched in and emaciated. I suspect she must be grazing on the natural fodder in your aquarium or her abdomen would be sunken in by now. That may be another reason why she is hanging out in the back of the aquarium — that could be where the hunting is best since amphipods and copepods like to hide out in the dark nooks and crannies amidst the rockwork and coral. If your mandarin fish is always hanging out nearby, perhaps they have both been grazing on pods a lot lately…
As long as a seahorse is in good condition to begin with (and the healthy-looking girth on your female would suggest that she seems to fall in that category, at least at this point), a seahorse can fast for several days with no ill effects whatsoever. In fact, when I’m going to be away from home for a weekend or up to three days at a time, I simply let my aquarium fish fast in my absence. I find that it’s safer and healthier to fast my livestock rather than turning them over to the care of an inexperienced fish sitter (fish tenders that are unfamiliar with seahorses ALWAYS tend to overfeed). If your female is indeed feeding secretively in order to avoid your male and is grazing on the pods in your tank, that may be enough to keep her going indefinitely (or at least until the pod population in your aquarium becomes depleted and the pickings get too slim).
I am somewhat concerned that she did not eat even within the safety of the breeder net, but she could have been off her feed because she was stressed out after being handled and confined in such a restricted space. Seahorses feel vulnerable and exposed in a situation like that where there is no shelter or cover available to them. The way she was just swimming agitatedly about in the breeder net could indicate that she was far from relaxed in those surroundings, and that may be why she refused to eat.
I still think that setting up a second feeding station may be worth a try in your case, Seagazer. I would try putting up another feeder towards the back of the tank where your female tends to hang out. Feed the other seahorses their fill at the old feeding station as usual, and if your female refuses to join them after a half-hour or so, try feeding her at the new feeding station near the back. That way, if your isolated female doesn’t feel welcome at the communal feeding trough, the males can monopolize it all they please, and your lonely female can have the new feeding station all to herself.
In the meantime, if possible, try carefully target feeding your female. I realize that may not be feasible if she has taken to hiding out in inaccessible areas, or if she’s so skittish now that she shys away whenever the feeding wand or baster approaches.
In that event, you might consider plying her with live foods. I would feed the other seahorses their fill of frozen Mysis and then introduce a generous portion of enriched adult brine shrimp (Artemia) or red feeder shrimp (Halocaridina rubra). Feeder shrimp will typically seek out the shelter of the rockwork and some of them at least should make their way back to where your female has been hiding out lately. That’s not a long-term solution, of course, but it may buy you some time while she is getting comfortable using the new feeder.
You might also try switching things up and confining the alpha male who has been doing most of the bullying in the breeder net or critter keeper for a day or two, rather than your omega female. That sometimes works with territorial fish like an aggressive angelfish that is persecuting a new arrival. Confining the bowling behind a sheet of glass or within a critter keeper for a time while the newcomer gets more comfortable in the aquarium sometimes defuses the situation. But I’ve never had occasion to try that with a belligerent seahorse, so I have no idea if it would be effective in breaking your alpha male of his habit of bullying.
But the first thing I would suggest is to perform a 25%-35% water change in conjunction with a little judicious aquarium cleaning. When a seahorse goes off its feed for no apparent reason, it’s often an indication of declining water quality. Your water chemistry may look great, but a lot of sneaky water quality problems don’t show up on the usual test kits, such as transitory ammonia spikes following a heavy feeding, low O2/high CO2 levels, pH drift, nutrient loading, depleted trace elements, etc.. Many times a water change and careful cleanup will set things right and perk up a flagging appetite.
If all else fails, and your female begins to lose condition and drop weight, it may be necessary to tube feed her in order to keep her strength up and provide her with nutritional support. But that’s not a long-term solution, either, Seagazer, so if it comes to that, it may be time true consider relocating the female that’s getting picked on. If she is consistently being bullied, sooner or later this stress will take a toll on your female, if it hasn’t already, so in that event, removing her from the source of that stress may be the best thing you can do to help. Hopefully, you have more than one marine aquarium and could simply transfer her to another suitable tank. If not, perhaps you know a fellow seahorse keeper who’s a friend or neighbor that may be willing to arrange a swap.
Please let us know right away if your female develops any other symptoms that could indicate a problem other than some stressful interactions with their tankmates. Keep an eye out for white, stringy feces, which could indicate intestinal flagellates or an inadequate diet.
Best of luck integrating your social outcast into the rest of the herd, Seagazer. Here’s hoping she works out her place in the social hierarchy and is eating like a horse again real soon!